Newbie questions about 64-bit systems

[Humga]

I'm a very experienced computer system builder But so far all systems
I've built are around the Athlon XP 32-bit ones. Never touched any 64-bit
stuff.

So could anyone (preferably those who has a 64-bit AMD and had used an AMD
32-bit CPU/mobo) point out the most important things I need to know before I
proceed onto built my friend's new 64-bit pc?

eg, Do existing PCI cards work with a 64-bit mobo?
eg, Do they still use FSBxMultiplier = speed?
eg, Will existing applications work? Will there be exceptions? How about
games (and 3D DX9.. ones)?
eg, Power supply standards?


Thak you very much

 

[Humga]

Thank you all for your info...really give me confidence

One more thing, what's this 939 and 754 version of the AMD cpu? This related
to slot type?

And I thought I knew it all until I bumped into 3 64-bit chips :X ...
Athlon 64, Opteron and FX51...what are they? What's the main differences?

Thanks a lot.

 

[General Schvantzkoph]

Thank you all for your info...really give me confidence

One more thing, what's this 939 and 754 version of the AMD cpu? This related
to slot type?

And I thought I knew it all until I bumped into 3 64-bit chips :X ...
Athlon 64, Opteron and FX51...what are they? What's the main differences?

Thanks a lot.

There are three flavors of Opterons and two flavors of Athlon64s, and to
make it even more confusing there is a version of the Athlon 64FX that is
really and Opteron.

The Opterons (all 940 pin) are the

1xx family, Used for single processor systems. None of the hypertransport
buses have coherency logic. (Coherency logic watches a bus to see which
words of memory are modified by another device on the bus and then makes
sure that the internal cache isn't storing a stale value, it's necessary
for shared memory multi-processors).

2xx family, Used for dual processor systems. One of the three
hypertransport buses has coherency logic. That bus connects the two CPUs
together, the others are used for IO.

4xx family, Used for larger multiprocessors. All three hypertransport
buses are coherent.

The Athlon 64s,

The 754 pin version has one DDR channel. There is no coherency logic on
the hypertransport.

The 940 pin Athlon64FX. This is a rebadged Opteron 1xx. Lacks the Cool and
Quiet logic of the other Athlon 64s, requires registered DDR memory
(slightly higher access time than the unbuffered DDRs used by the other
Athlon 64s but it's more reliable and can support larger DIMMs).

The 939 pin Athlon64FX. This is the latest version of the chip. It has
dual DDR like the Opterons but will work with unbuffered DIMMs and has
support for Cool and Quiet. The cache size is only 1/2M vs 1M on the
Opterons and the Athlon 64 754. The higher memory bandwidth and lower RAM
access times compensate for the smaller cache size so clock for clock the
performance is similar or better than the 754 pin parts, probably slightly
worse than the Opterons which enjoy both a large cache and dual DDR.

 

[Humga]

There are three flavors of Opterons and two flavors of Athlon64s, and to
make it even more confusing there is a version of the Athlon 64FX that is
really and Opteron.
....

Now I lost confidence again... :X

I'll read carefully what you wrote...very interesting indeed! And thanks for
the time

 

[Humga]

There are three flavors of Opterons and two flavors of Athlon64s, and to
make it even more confusing there is a version of the Athlon 64FX that is
really and Opteron.


The Opterons (all 940 pin) are the

1xx family, Used for single processor systems. None of the hypertransport
buses have coherency logic. (Coherency logic watches a bus to see which
words of memory are modified by another device on the bus and then makes
sure that the internal cache isn't storing a stale value, it's necessary
for shared memory multi-processors).

I think I'll be looking into these.

2xx family, Used for dual processor systems. One of the three
hypertransport buses has coherency logic. That bus connects the two CPUs
together, the others are used for IO.

4xx family, Used for larger multiprocessors. All three hypertransport
buses are coherent.

Not for me...phew!

The Athlon 64s,

The 754 pin version has one DDR channel. There is no coherency logic on
the hypertransport.

The 940 pin Athlon64FX. This is a rebadged Opteron 1xx. Lacks the Cool and
Quiet logic of the other Athlon 64s, requires registered DDR memory
(slightly higher access time than the unbuffered DDRs used by the other
Athlon 64s but it's more reliable and can support larger DIMMs).

The 939 pin Athlon64FX. This is the latest version of the chip. It has
dual DDR like the Opterons but will work with unbuffered DIMMs and has
support for Cool and Quiet. The cache size is only 1/2M vs 1M on the
Opterons and the Athlon 64 754. The higher memory bandwidth and lower RAM
access times compensate for the smaller cache size so clock for clock the
performance is similar or better than the 754 pin parts, probably slightly
worse than the Opterons which enjoy both a large cache and dual DDR.

So from reading what you wrote first came the Opteron then the Athlon64 and
finally the AthlonFX. Correct?

And the technology gets better (hence more faster) sequentially as above.
Correct?

My friend wants one from the latest family AMD CPUs so choosing an Athlon64
is the right way to go?

754 pin is "single DDR channel". This isn't related to the number of DDR RAM
sticks on the mobo is it?

 

[General Schvantzkoph]

I think I'll be looking into these.


Not for me...phew!


So from reading what you wrote first came the Opteron then the Athlon64
and finally the AthlonFX. Correct?

And the technology gets better (hence more faster) sequentially as
above. Correct?

Not correct. The Opterons are server oriented. They came first and they
are still as fast as any part. The Opterons have bigger caches than the
939 pin Athlon64FXs and they have twice the memory bandswidth of the
Athlon 64 754 pin parts.

My friend wants one from the latest family AMD CPUs so choosing an
Athlon64 is the right way to go?

The right way to go is the 939 pin AthlonFX with a motherboard using the
Nvidia Nforce 3-250GB chipset. For desktop applications the 939s have a
small advantage over the older Opterons because the hypertransport runs at
1GHz rather than 800MHz. They also run cooler because of the Cool and
Quiet. The Nforce 3-250GB also has a very fast gigabit ethernet controller
on chip. The only board supporting the Nvidia ethernet at the moment is
the MSI K8N Neo2 Platinum which just started shipping.

754 pin is "single DDR channel". This isn't related to the number of DDR
RAM sticks on the mobo is it?

It is related. The single channel limits the number of DIMMs to three, all
of which are on the same bus so the signal integrity is marginal for a
fully loaded system. The dual channel parts (the 940s and the 939s) have
two DIMMs per bus for a total of four. Because there are only two DIMMs
per bus the memory system is more robust. The 940 pin parts use registered
DIMMs which further improve the signal integrity, but at the expense of
slightly longer memory access times. Because the registered DIMMs have
register which isolate the RAMs from the bus it's also possible for the
DIMMs to have more RAMs on them so you can have more total RAM. However
for a desktop system you won't need to use 2G DIMMs. I'd suggest staring
with a pair of 512M DIMMs (for a total of 1G). That's plenty of RAM for
most desktop applications. You will still have two vacant sockets so in a
year, when 1G DIMMs get cheap, you could add a pair of 1G DIMMs which
would give you 3Gs of memory.

I don't know which OS you are planning on using. Linux fully supports the
Amd64 today, WinXP won't have support (except in beta form) until the end
of Q2 next year. So if you want to take advantage of all of the features
of the AMD64, including large memory systems (>4G), and the extra
registers in the AMD architecture use Mandrake 10 or SUSE 9.1 (I prefer
Mandrake).

 

[Humga]

The right way to go is the 939 pin AthlonFX with a motherboard using the
Nvidia Nforce 3-250GB chipset. For desktop applications the 939s have a
small advantage over the older Opterons because the hypertransport runs at
1GHz rather than 800MHz. They also run cooler because of the Cool and
Quiet. The Nforce 3-250GB also has a very fast gigabit ethernet controller
on chip. The only board supporting the Nvidia ethernet at the moment is
the MSI K8N Neo2 Platinum which just started shipping.

I've done a little research into the 939 pin versions and *phawww* they cost
a bomb - maybe not exactly a bomb but they do cost a lot...

Pricewise, I think the 754 pin Athlon 64 is more realistic for home
gaming/office

It is related. The single channel limits the number of DIMMs to three, all
of which are on the same bus so the signal integrity is marginal for a
fully loaded system. The dual channel parts (the 940s and the 939s) have
two DIMMs per bus for a total of four. Because there are only two DIMMs
per bus the memory system is more robust. The 940 pin parts use registered
DIMMs which further improve the signal integrity, but at the expense of
slightly longer memory access times. Because the registered DIMMs have
register which isolate the RAMs from the bus it's also possible for the
DIMMs to have more RAMs on them so you can have more total RAM. However
for a desktop system you won't need to use 2G DIMMs. I'd suggest staring
with a pair of 512M DIMMs (for a total of 1G). That's plenty of RAM for
most desktop applications. You will still have two vacant sockets so in a
year, when 1G DIMMs get cheap, you could add a pair of 1G DIMMs which
would give you 3Gs of memory.

I personally have an nForce2 (ASUS A7N8X) and I think I know what you meant
by single channel (CPU). I have 2 512MB PC3200 DIMMs and they utilise this
"dual-channel" feature on the mobo...apparently gives it better performance.
Athon XP are single channel right?

I don't know which OS you are planning on using. Linux fully supports the
Amd64 today, WinXP won't have support (except in beta form) until the end
of Q2 next year. So if you want to take advantage of all of the features
of the AMD64, including large memory systems (>4G), and the extra
registers in the AMD architecture use Mandrake 10 or SUSE 9.1 (I prefer
Mandrake).

I've used Linux Red Hat 9.0 before and because I had been a Windows user for
such a long time I really cannot find (due to poor knowledge) it easy to
learn :X In the end I formatted the hard drive and reinstalled Windows
XP...I know what you Linux users are thinking right now

Back to the main topic, I guess my friend still wants the 64-bit CPU because
it sounds good...but without any real performance boost...I don't care
because he is the one paying for the components

 

[Wes Newell]

One more thing, what's this 939 and 754 version of the AMD cpu? This related
to slot type?

Number of socket pins, 754 and 939, and then there's 940 that will be
around a long time I think. It takes Opteron's and older FX cpu's.

And I thought I knew it all until I bumped into 3 64-bit chips :X ...
Athlon 64, Opteron and FX51...what are they? What's the main
differences?

754 supports only single channel CPU's. Standard A64's and now Semprons,
which is a story within itself.

940 is the original dual channel board that supported Opterons an FX's.
Opterons are capable of up to 8-way. FX's are single cpu only. These
require registered ram. It doesn't have to be buffered.

939 is the new board that supports an dual channel 939 cpu, A64 or FX,
and uses standard DDR ram.

At current time, the 3700+ is the fastest cpu slated for the 754 board.

Single channel is not much of a drawback unless you run bandwidth
benchmarks all the time. It's a little faster than the single channel cpu,
all other things being equal.

There's lots of choices now. And any would be more than enough speed for
most people. So step up and pull out your wallet.

 

[Jason Cothran]

|
| |
| > On Mon, 02 Aug 2004 20:56:10 +0100, Humga wrote:
| > > My friend wants one from the latest family AMD CPUs so choosing an
| > > Athlon64 is the right way to go?
| >
| > The right way to go is the 939 pin AthlonFX with a motherboard using the
| > Nvidia Nforce 3-250GB chipset. For desktop applications the 939s have a
| > small advantage over the older Opterons because the hypertransport runs
at
| > 1GHz rather than 800MHz. They also run cooler because of the Cool and
| > Quiet. The Nforce 3-250GB also has a very fast gigabit ethernet
controller
| > on chip. The only board supporting the Nvidia ethernet at the moment is
| > the MSI K8N Neo2 Platinum which just started shipping.
|
| I've done a little research into the 939 pin versions and *phawww* they
cost
| a bomb - maybe not exactly a bomb but they do cost a lot...
|
| Pricewise, I think the 754 pin Athlon 64 is more realistic for home
| gaming/office
|
| >
| > > 754 pin is "single DDR channel". This isn't related to the number of
DDR
| > > RAM sticks on the mobo is it?
| >
| > It is related. The single channel limits the number of DIMMs to three,
all
| > of which are on the same bus so the signal integrity is marginal for a
| > fully loaded system. The dual channel parts (the 940s and the 939s) have
| > two DIMMs per bus for a total of four. Because there are only two DIMMs
| > per bus the memory system is more robust. The 940 pin parts use
registered
| > DIMMs which further improve the signal integrity, but at the expense of
| > slightly longer memory access times. Because the registered DIMMs have
| > register which isolate the RAMs from the bus it's also possible for the
| > DIMMs to have more RAMs on them so you can have more total RAM. However
| > for a desktop system you won't need to use 2G DIMMs. I'd suggest staring
| > with a pair of 512M DIMMs (for a total of 1G). That's plenty of RAM for
| > most desktop applications. You will still have two vacant sockets so in
a
| > year, when 1G DIMMs get cheap, you could add a pair of 1G DIMMs which
| > would give you 3Gs of memory.
|
| I personally have an nForce2 (ASUS A7N8X) and I think I know what you
meant
| by single channel (CPU). I have 2 512MB PC3200 DIMMs and they utilise this
| "dual-channel" feature on the mobo...apparently gives it better
performance.
| Athon XP are single channel right?

Not exactly. The Athlon XP alone doesn't dictate the number of memory
channels. They don't have the memory controller on die. That is one of the
big advantages of the A64. If you have a dual channel motherboard with an
Athlon XP, you can run dual channels of RAM.


|
| > I don't know which OS you are planning on using. Linux fully supports
the
| > Amd64 today, WinXP won't have support (except in beta form) until the
end
| > of Q2 next year. So if you want to take advantage of all of the features
| > of the AMD64, including large memory systems (>4G), and the extra
| > registers in the AMD architecture use Mandrake 10 or SUSE 9.1 (I prefer
| > Mandrake).
|
| I've used Linux Red Hat 9.0 before and because I had been a Windows user
for
| such a long time I really cannot find (due to poor knowledge) it easy to
| learn :X In the end I formatted the hard drive and reinstalled Windows
| XP...I know what you Linux users are thinking right now
|
| Back to the main topic, I guess my friend still wants the 64-bit CPU
because
| it sounds good...but without any real performance boost...I don't care
| because he is the one paying for the components
|

The A64 still gives a considerable real performance boost, even ina 32-bit
environment. It will be money well spent.

 

[Wes Newell]

The right way to go is the 939 pin AthlonFX with a motherboard using the
Nvidia Nforce 3-250GB chipset. For desktop applications the 939s have a
small advantage over the older Opterons because the hypertransport runs at
1GHz rather than 800MHz. They also run cooler because of the Cool and
Quiet. The Nforce 3-250GB also has a very fast gigabit ethernet controller
on chip. The only board supporting the Nvidia ethernet at the moment is
the MSI K8N Neo2 Platinum which just started shipping.

I think you're assuming money is no object. While the FX may certainly be
the fastest way to go, I wouldn't say it was the right way without more
details on how much money he's willing to pay for top of the line, which
he probably doesn't need. A 754 system would only be about 1/4 the price
of the FX system and would run within 80% of the speed of the FX.

 

[General Schvantzkoph]

I've done a little research into the 939 pin versions and *phawww* they cost
a bomb - maybe not exactly a bomb but they do cost a lot...

Pricewise, I think the 754 pin Athlon 64 is more realistic for home
gaming/office


I personally have an nForce2 (ASUS A7N8X) and I think I know what you meant
by single channel (CPU). I have 2 512MB PC3200 DIMMs and they utilise this
"dual-channel" feature on the mobo...apparently gives it better performance.
Athon XP are single channel right?

There is an important difference. The dual memory interfaces on the
AMD64s are on the CPU chip itself so the CPU is able to take full
advantage of the extra bandwidth. The Athlon XP had a front side bus which
limited the amount of bandwidth that it could use to what was available
from a single DDR channel. The extra bandwidth of the Nforce 2 was mostly
wasted because of the frontside bus bottleneck on the AthlonXP.

I've used Linux Red Hat 9.0 before and because I had been a Windows user
for such a long time I really cannot find (due to poor knowledge) it
easy to learn :X In the end I formatted the hard drive and reinstalled
Windows XP...I know what you Linux users are thinking right now

Back to the main topic, I guess my friend still wants the 64-bit CPU
because it sounds good...but without any real performance boost...I
don't care because he is the one paying for the components

If cost is your primary driver then the 754 pin Athlon 64 is your best
choice. Get the Athlon 64 3200+. Try to find one with 1M cache, they make
them with both 1/2M and 1M. Also get a motherboard with either the Nvidia
Nforce 3-250 (NOT the -150!!!) or the VIA chipset.

 

[Yousuf Khan]

Now I lost confidence again... :X

I'll read carefully what you wrote...very interesting indeed! And
thanks for the time

Summary:
Socket 754 (single channel RAM): Athlon 64 (older)
Socket 939 (dual channel RAM): Athlon 64 (newer), Athlon 64 FX53 and above
Socket 940 (dual channel buffered RAM): Opterons (all versions), Athlon 64
FX (FX51 and early version of FX53).

Athlon 64's come in versions ranging from 512K to 1MB of L2 cache. All
Athlon 64FX's come with 1MB of L2. All Opterons are also all 1MB.

Yousuf Khan

 

[Jason Cothran]

| Humga wrote:
| > | >
| >> There are three flavors of Opterons and two flavors of Athlon64s,
| >> and to make it even more confusing there is a version of the Athlon
| >> 64FX that is really and Opteron.
| >> ....
| >
| > Now I lost confidence again... :X
| >
| > I'll read carefully what you wrote...very interesting indeed! And
| > thanks for the time
|
| Summary:
| Socket 754 (single channel RAM): Athlon 64 (older)
| Socket 939 (dual channel RAM): Athlon 64 (newer), Athlon 64 FX53 and above
| Socket 940 (dual channel buffered RAM): Opterons (all versions), Athlon 64
| FX (FX51 and early version of FX53).
|
| Athlon 64's come in versions ranging from 512K to 1MB of L2 cache. All
| Athlon 64FX's come with 1MB of L2. All Opterons are also all 1MB.
|
| Yousuf Khan
|

Socket 754 is/will also be used for sempron 3100+ and newer

 

[Humga]

Summary:
Socket 754 (single channel RAM): Athlon 64 (older)
Socket 939 (dual channel RAM): Athlon 64 (newer), Athlon 64 FX53 and above
Socket 940 (dual channel buffered RAM): Opterons (all versions), Athlon 64
FX (FX51 and early version of FX53).

Athlon 64's come in versions ranging from 512K to 1MB of L2 cache. All
Athlon 64FX's come with 1MB of L2. All Opterons are also all 1MB.

Nice summary! Confidence level gained: 80%