AGP vs PCI-E - how big is the difference?

[BrockLanders]

Hello. I have a 9800pro, I'm looking to upgrade to something that's
capable of running Roboblitz. My mobo only supports AGP and I'm
wondering if it would be wiser to buy a lower-priced card for now and
wait til I upgrade to a motherboard that supports PCI-E (which I won't
be doing soon) to buy a more expensive card. I guess what I'm asking
is how does the AGP version of a card compare to the PCI-E version of
the same card? Is the performance gap large enough to make buying an
AGP card in the $200.00 U.S. range a waste of money?

 

[John Doe]

Hello. I have a 9800pro, I'm looking to upgrade to something
that's
capable of running Roboblitz. My mobo only supports AGP and I'm
wondering if it would be wiser to buy a lower-priced card for now
and wait til I upgrade to a motherboard that supports PCI-E (which
I won't be doing soon) to buy a more expensive card. I guess what
I'm asking is how does the AGP version of a card compare to the
PCI-E version of the same card? Is the performance gap large
enough to make buying an AGP card in the $200.00 U.S. range a
waste of money?

The selection of high-performance PCI-E is huge compared to the
selection of AGP video cards. That was a major factor that got me to
upgrade the mainboard/CPU. I probably shouldn't have spent money on
an AGP upgrade first, from a lesser card than yours.

If you want to know what card might run your game, find a
group/forum with players of that game. The users are the ones who
know what hardware works.

Good luck and have fun.

 

[BigJim]

what kind of processor do you have and how much ram.
there is no sense to buy a high end agp card if your cpu and ram will slow
it down.

 

[Conor]

Hello. I have a 9800pro, I'm looking to upgrade to something that's
capable of running Roboblitz. My mobo only supports AGP and I'm
wondering if it would be wiser to buy a lower-priced card for now and
wait til I upgrade to a motherboard that supports PCI-E (which I won't
be doing soon) to buy a more expensive card. I guess what I'm asking
is how does the AGP version of a card compare to the PCI-E version of
the same card? Is the performance gap large enough to make buying an
AGP card in the $200.00 U.S. range a waste of money?

THere are companies releasing top end AGP cards. You can buy a Geforece
7600 and an ATI 1900XL is on its way in AGP form - both of which are
more than enough.

 

[fwibbler]

THere are companies releasing top end AGP cards. You can buy a Geforece
7600 and an ATI 1900XL is on its way in AGP form - both of which are
more than enough.

Yes, and benchtests by various websites have shown that the PCIe cards
perform very little better than the AGP couterparts even on these high-end
cards.

This will probably change in time, but not yet.

Cheers!

 

[BrockLanders]

Yes, and benchtests by various websites have shown that the PCIe cards
perform very little better than the AGP couterparts even on these high-end
cards.

This will probably change in time, but not yet.

Cheers!

Do you have any links to these websites? I would like to have a look
at the comparisons.

And thanks to everyone for the replies.

 

[Mike T.]

Do you have any links to these websites? I would like to have a look
at the comparisons.

And thanks to everyone for the replies.

There's no need to look at the comparisons. There isn't a video card
released (to date) that will be slowed down (even slightly) by the bandwidth
of the AGP bus. Any "differences" in speed of AGP vx. PCI-Express are
usually related to some 'kludge' that a manufacturer comes up with to force
a card to work on the other bus. For example, card AX8579 (made up model)
is AGP only, but XFX puts a PCI-Express bridge on it to allow the card to be
sold as PCI-Express. Now the card is slightly slowed down by the added
chip(s). This is because it is an AGP card running on a PCI-Express bus.
The same thing can happen if you force a PCI-Express video card to run on a
AGP mainboard, using some kind of bridge chip(s). The AGP version will be
slowed down very slightly, because it is a PCI-Express card running in an
AGP slot. -Dave

 

[Frank McCoy]

There's no need to look at the comparisons. There isn't a video card
released (to date) that will be slowed down (even slightly) by the bandwidth
of the AGP bus.

That's assuming your motherboard supports full speed AGP ...
preferably 8x.

But then: if not, why are you bothering to compare?

Any "differences" in speed of AGP vx. PCI-Express are
usually related to some 'kludge' that a manufacturer comes up with to force
a card to work on the other bus. For example, card AX8579 (made up model)
is AGP only, but XFX puts a PCI-Express bridge on it to allow the card to be
sold as PCI-Express. Now the card is slightly slowed down by the added
chip(s). This is because it is an AGP card running on a PCI-Express bus.
The same thing can happen if you force a PCI-Express video card to run on a
AGP mainboard, using some kind of bridge chip(s). The AGP version will be
slowed down very slightly, because it is a PCI-Express card running in an
AGP slot. -Dave

The selling point of PCI-Express, is that it's newer and thus
*supposedly* better and faster. Maybe it *will* be ... someday.

 

[Dave]

The selling point of PCI-Express, is that it's newer and thus
*supposedly* better and faster. Maybe it *will* be ... someday.

MY prediction:

Video cards/GPUs will get fast enough to almost take advantage of the extra
bandwidth of PCI-Express X16, right around the same time that some new (and
larger bandwidth) bus technology is fielded. -Dave

 

[johns]

And that area may already be here. I have 2 PCs.
One is AGP running a ATI 9800. The other is PCI-e
running an nVidia 7900. I see a huge difference in
gaming, but I also see a huge difference in the
PVR performance I have in each. The AGP uses
a Hauppauge 350 on the pci bus, and it has big
problems with audio-video sync. The PCI-e uses
an ATI 550 Pro in a pci-e X1 slot, and it has no
problem with audio-video sync. And this weekend,
I was looking at new LCD-TVs with DVR top boxes.
Guess what ? The DVR cannot keep audio-video
sync'd when using satilite reception. There is your
11 billion $$$ industry crapping out because their
DVRs are not fast enough ... pci bus no doubt
with AGP video. You are not going to hang an
ATI TV-box that sends your PC movies to your
TV set on a PCI bus.

johns

 

[Frank McCoy]

MY prediction:

Video cards/GPUs will get fast enough to almost take advantage of the extra
bandwidth of PCI-Express X16, right around the same time that some new (and
larger bandwidth) bus technology is fielded. -Dave

Sounds like a good prediction to me.

 

[Paul]

MY prediction:

Video cards/GPUs will get fast enough to almost take advantage of the
extra bandwidth of PCI-Express X16, right around the same time that some
new (and larger bandwidth) bus technology is fielded. -Dave

Here is an article comparing X1950Pro AGP versus PCI Express. They are
still in the same ball park. The bus interface doesn't seem to be making
much of a difference. (There might have been another article like this,
but I could not find it.)

http://www.firingsquad.com/hardware/sapphire_x1950_pro_agp_ultimate_review/page5.asp

This article charts how much of an effect the PCI Express lane count, makes
on performance. (The links to the English version of the article appear to be
broken, so I had to use the German version.) Page 10, shows SpecViewPerf, which
is an X-Windows benchmark. The games benchmarks on page 11 are less affected
by the bus performance. By using cello tape on the pins of the PCI Express
video card, they can test x1, x2, x4, x8, and x16 bus performance.

http://hardware.thgweb.de/2004/11/05/pci_express_durchleuchtet_alle_modi_im_test/page10.html
http://hardware.thgweb.de/2004/11/05/pci_express_durchleuchtet_alle_modi_im_test/page11.html

*******

And finally, there is a newer standard coming out soon. PCI Express 2.0
allows a lane to go faster, but it is unclear what positive effect this
will have for video.

"PCI Express 2.0 nears completion"
http://news.com.com/PCI+Express+2.0+nears+completion/2100-1006_3-6123758.html

http://en.wikipedia.org/wiki/PCI_Express

"PCI Express 2.0

PCI-SIG announced the availability of the PCI Express Base 2.0 specification
on 15 January 2007.[2] PCIe 2.0 doubles the bus standard's bandwidth from
2.5Gbps to 5Gbps, meaning a x32 connector can transfer data at up to near 16GBps.
PCIe 2.0 is still compatible with PCIe 1.1, so older cards will still be able
to work in machines with this new version.

The PCI-SIG also said PCIe 2.0 also features improvements to the point-to-point
data transfer protocol and its software architecture.[3] Intel is expected to
release its first chipsets supporting PCIe 2.0 in the second quarter of 2007
with its 'Bearlake' family. AMD starts supporting PCIe 2.0 from its RD700
chipset series. NVIDIA has revealed that the MCP72 will be their first
PCIe 2.0 equipped chipset.[4]"

The problem with fattening up the PCI Express bus, is that the rest of the
busses needed, may not be ready for it. For example, on an Athlon64 system,
video card traffic travels over the HT bus, to get to the processor and its
memory controller. That bandwidth is just enough to match a single PCI Express
x16 rate interface. Increasing the effective lane clock rates would be a waste
of time, if the processor interface remains the same. (As it is, there were
motherboards in the past, with two x16 slots, but the slots could not run
full blast simultaneously.)

And on the Intel architecture, a question would be, what bandwidth can the
memory controller sustain, if there was a PCI Express 2.0 x16 video slot
DMA transferring to it.

It will be interesting to see what new power level the Northbridge chips
will have, with PCI Express 2.0 lanes on them. As it is, while processor
power consumption in idle is improving with time, modern Northbridge
chips only seem to be growing in power consumption. PCI Express 2.0 won't
help matters.

HTH,
Paul

 

[btcruz]

Here's my recent AGP experience:

I have an older Aopen AK86-L mobo with an Athlon XP 64 3200+ (754
pin), 1GB of Corsair XMS CAS2 memory and a Radeon 9800Pro vid
card....this box has been absolutely rock solid since I built it
several years ago. My old Samsung 19" CRT monitor finally gave up the
ghost and I decided to finally get into the modern world and upgrade
to a widescreen LCD. The problem was I needed a new video card to
drive it so I opted to try one of the newer AGP cards and that's where
the nightmare began.

The first card was a Radeon X1650Pro (512MB of DDR2 memory). Upon
initial install, I could get to the desktop in VGA mode, but any
change of resolution and the screeen would go blank with no video
signal. So, I set out to update every driver I could. I went to
Aopen's site and got the latest BIOS for the board and flashed it,
updated the Catalyst drivers, etc. This seemed to fix the issues as I
was now running my desktop at 1440x900 resolution (native res for my
19" monitor). Thought things would be fine until I tried to run some
games. Anyhting 3D would cause the screen to go blank again.

After much more futzing aroud with this card I took it back and
exchanged it for a Radeon X1600XT (256MB of DDR3 memory and a lot
higher clock rates than the XX50 line of cards). The 1600XT did
marginally better as I was able to actually launch and play games and
it too would go blank. There was no pattern to how long it would
last, sometimes it would lock up or blank out immediately upon
launching a game, or sometimes it would go 10, 15, 20 minutes or
more. Again, driver updates, tweaks, reading forums, all manner of
fixes I could find to no avail. When it did work, the frame rates
were terrible and I had to play all games at the lowest settings just
to make it managable.

I took this card back and decided to try an Nvidia card. I got a
7600GS AGP card and took it home and installed it. Couldn't get any
video out of it at all, not even to the desktop in forced VGA mode. I
even tried switching the monitor cable from digital to analog, no
luck.

Took this card back and just reinstalled my old Radeon 9800Pro (so I
could at least check e-mail, etc) until I figured out what to do. I
discovered on some forums that several other folks have had similar
issues recently with other motherboards as well.

Then I started looking on newegg and found a great deal. For only $65
more than the price of those AGP video cards alone, I got a Foxconn
nforce 4 SLI motherboard, Athlon 64 4000+ (939 pin) CPU and an Nvidia
7900GS video card (PCI Express 16x)!!!!!! I just reused my old
Corsair PC3200 memory (and am also now able to run them at max timings
of 2-3-3-6!) Voila!! Now I play World of Warcraft at max settings,
Nvidia's 2Q anti-aliasing setting, max anisotropic filtering (16x),
and all 3D set to maximum quality at 1440x900 resolution an never go
below 60 FPS!!!!

So, although the PCIE bus may not be any faster than the old 8x AGP
bus (yet), it seems some of the older AGP based mobos aren't working
well with the new AGP cards. If my personal experience is any
indicator, save yourself the headaches and upgrade the mobo, processor
and video card all at once.

I went with the 939 pin setup because I am on a very limited budget
and needed to be able to reuse my memory. The AM2 socket boards and
the newer dual core CPU's use DDR2 memory, so that was an extra
expense I could not afford right now. I was worried the Athlon 4000
and 7900GS would still be marginal on the frame rates, but it sure was
a nice surprise to see it isn't! This thing works very well and this
was the first system I've ever built that started right up without a
hiccup when everything was installed and powered on for the first
time. Very little setup/tweaking was required to get max
performance. I'm very impressed with the Foxconn board and even more
so when I consider how cheap this overall upgrade was.

 

[JAD]

Here's my recent AGP experience:

I have an older Aopen AK86-L mobo with an Athlon XP 64 3200+ (754
pin), 1GB of Corsair XMS CAS2 memory and a Radeon 9800Pro vid
card....this box has been absolutely rock solid since I built it
several years ago. My old Samsung 19" CRT monitor finally gave up the
ghost and I decided to finally get into the modern world and upgrade
to a widescreen LCD. The problem was I needed a new video card to
drive it so I opted to try one of the newer AGP cards and that's where
the nightmare began.

The first card was a Radeon X1650Pro (512MB of DDR2 memory). Upon
initial install, I could get to the desktop in VGA mode, but any
change of resolution and the screeen would go blank with no video
signal. So, I set out to update every driver I could. I went to
Aopen's site and got the latest BIOS for the board and flashed it,
updated the Catalyst drivers, etc. This seemed to fix the issues as I
was now running my desktop at 1440x900 resolution (native res for my
19" monitor). Thought things would be fine until I tried to run some
games. Anyhting 3D would cause the screen to go blank again.

After much more futzing aroud with this card I took it back and
exchanged it for a Radeon X1600XT (256MB of DDR3 memory and a lot
higher clock rates than the XX50 line of cards). The 1600XT did
marginally better as I was able to actually launch and play games and
it too would go blank. There was no pattern to how long it would
last, sometimes it would lock up or blank out immediately upon
launching a game, or sometimes it would go 10, 15, 20 minutes or
more. Again, driver updates, tweaks, reading forums, all manner of
fixes I could find to no avail. When it did work, the frame rates
were terrible and I had to play all games at the lowest settings just
to make it managable.

I took this card back and decided to try an Nvidia card. I got a
7600GS AGP card and took it home and installed it. Couldn't get any
video out of it at all, not even to the desktop in forced VGA mode. I
even tried switching the monitor cable from digital to analog, no
luck.

Took this card back and just reinstalled my old Radeon 9800Pro (so I
could at least check e-mail, etc) until I figured out what to do. I
discovered on some forums that several other folks have had similar
issues recently with other motherboards as well.

Then I started looking on newegg and found a great deal. For only $65
more than the price of those AGP video cards alone, I got a Foxconn
nforce 4 SLI motherboard, Athlon 64 4000+ (939 pin) CPU and an Nvidia
7900GS video card (PCI Express 16x)!!!!!! I just reused my old
Corsair PC3200 memory (and am also now able to run them at max timings
of 2-3-3-6!) Voila!! Now I play World of Warcraft at max settings,
Nvidia's 2Q anti-aliasing setting, max anisotropic filtering (16x),
and all 3D set to maximum quality at 1440x900 resolution an never go
below 60 FPS!!!!

So, although the PCIE bus may not be any faster than the old 8x AGP
bus (yet), it seems some of the older AGP based mobos aren't working
well with the new AGP cards. If my personal experience is any
indicator, save yourself the headaches and upgrade the mobo, processor
and video card all at once.

I went with the 939 pin setup because I am on a very limited budget
and needed to be able to reuse my memory. The AM2 socket boards and
the newer dual core CPU's use DDR2 memory, so that was an extra
expense I could not afford right now. I was worried the Athlon 4000
and 7900GS would still be marginal on the frame rates, but it sure was
a nice surprise to see it isn't! This thing works very well and this
was the first system I've ever built that started right up without a
hiccup when everything was installed and powered on for the first
time. Very little setup/tweaking was required to get max
performance. I'm very impressed with the Foxconn board and even more
so when I consider how cheap this overall upgrade was.

this whole story sounds like a typical 'driver' issue. My first LCD was powered by a 8600
AIW ATI 128 AGP4 card 1600x1200

 

[Frank McCoy]

If my personal experience is any
indicator, save yourself the headaches and upgrade the mobo, processor
and video card all at once.

Probably good advice all around; whether going with AGP or PCI-Express.
While I personally like AGP; if I was "upgrading" the pair I'd probably
go with PCI-Express, for the sole reason that it's getting easier to
find high-end cards in that format ... Even ones like my favorite: The
ATI "All-In-Wonder" is easier to find in PCI-Express than AGP; though
they make it in both versions; and the specs are about identical.

So, if later on I need to replace the video board, I suspect it will be
much easier to find PCI-E rather than AGP in about two years or so.

And the price is about the same, too ... Only about 5% premium for
PCI-E.

 

[Frank McCoy]

In alt.comp.hardware.pc-homebuilt "JAD" <john

this whole story sounds like a typical 'driver' issue. My first LCD was powered by a 8600
AIW ATI 128 AGP4 card 1600x1200

I had to download brand new drivers for my new LCD screen.
The drivers even from six months ago wouldn't support 1680x1050.
Then, of course, we have the problem with Win-XP "Safe Mode" not
supporting LCD screens. A real PITA, if something goes wrong, the
system dies, and you want to fix things.

(XP assumes that any monitor will support VGA at 85hz ... LCD screens
*don't*. The problem is: You can select pure VGA from the F8 prompt, OR
"Safe Mode"; but not both. And, if things die, you can't get to the
msconfig utility which allows setting both, without being in Windows
first. Yes, if you have special tools and know what you're doing, you
CAN edit the BOOT.INI file manually ... But again that usually takes
being able to boot Windows first ... Catch-22. Especially since you
need Windows XP running to access the NTFS file-system. A "boot disk"
is no bloody help at all.)

 

[btcruz]

this whole story sounds like a typical 'driver' issue. My first LCD was powered by a 8600
AIW ATI 128 AGP4 card 1600x1200- Hide quoted text -

- Show quoted text -

Well, I tried every available driver I could find, including rolling
back to older drivers, several older BIOS versions, etc. I didn't
specify in the post every version I tried, I just said I tried every
thing I could. Nothing made a difference. When it would run, the
games were OK, just not great frame rates because I was apparently CPU
limited.

Resolution alone wasn't my only issue, I need to run at native
resolution (sorry, LCD's look like crap at anything other than native)
and still be able to play the games. I'm sure you could run at
1600x1200 with that vid card, but I seriously doubt it would work well
with modern games.

My old Radeon 9800 will run my desktop OK, but don't even think about
playing games with it at those resolutions....