A8N-SLI Overclocking Hyper Transport settings? Othe Advice needed

L

Leadfoot

Any one know where there is a good guide that will explain what the Hyper
Transport settings do in relation to overclocking and memory timings

A8N-SLI deluxe needed 8 SATA ports and 3 PCI slots. Wanted premium but have
Upside down Silverstone TJ-06 case

Athlon 64 3500+ venice retail BP @2700 11X245 1.55vdc P95 stable, not stable
@11X250, Stock heatsink

2 X 512MB Kingston HyperX PC3500 running @158FSB @2.5-6-3-3??? Hyperx 3200
is ASUS Qualified bit not HyperX PC3500? Could use some advice on whether
there is a better choice in a memory upgrade to get better memory
performance

I've had this up and running since Sunday night and really like this board
and processor. This A64 idles at 34C @1.55vdc and doesn't get much over 50C
with P95 Stress test set for FPU. Coolest processor I have ever owned

I tried for 3000MHZ with ClockGen for nVidia nForce4 but got a hard drive
pci.sys failure on reboot Good thing I have 7 hard drives on my box and
wasn't testing the primary windows system ;-)
 
P

Paul

"Leadfoot" said:
Any one know where there is a good guide that will explain what the Hyper
Transport settings do in relation to overclocking and memory timings

A8N-SLI deluxe needed 8 SATA ports and 3 PCI slots. Wanted premium but have
Upside down Silverstone TJ-06 case

Athlon 64 3500+ venice retail BP @2700 11X245 1.55vdc P95 stable, not stable
@11X250, Stock heatsink

2 X 512MB Kingston HyperX PC3500 running @158FSB @2.5-6-3-3??? Hyperx 3200
is ASUS Qualified bit not HyperX PC3500? Could use some advice on whether
there is a better choice in a memory upgrade to get better memory
performance

I've had this up and running since Sunday night and really like this board
and processor. This A64 idles at 34C @1.55vdc and doesn't get much over 50C
with P95 Stress test set for FPU. Coolest processor I have ever owned

I tried for 3000MHZ with ClockGen for nVidia nForce4 but got a hard drive
pci.sys failure on reboot Good thing I have 7 hard drives on my box and
wasn't testing the primary windows system ;-)
Click to expand...

The Hypertransport bus, is the bus that connects the processor to
the single chip chipset. The bus is 16 bits wide up and 16 bits
wide down, clocks at 1000MHz, uses DDR, and in each direction that
is 1000x2x16/8 = 4GB/sec bandwidth. That bandwidth is used to support
the PCI-Express I/O for the video card (x16 = 4GB/sec up/down as well).
It also supports disk I/O and any other chipset peripheral bandwidth.

Now, you would think, based on that arithmetic, that the Hypertransport
is not fast enough. But a PCI-E x16 video card only needs about x4
to give decent performance, so the performance seen is not as sensitive
to the bus speed, as the arithmetic would suggest.

In the BIOS, you are offered [Auto, 1x, 2x, 3x, 4x, 5x] as options for
"Hyper Transport Frequency". These multipliers are multiplied by the
CPU clock. The nominal CPU clock is 200MHz. The nominal HT bus limit
for your board is 1000MHz. That says, in a non-overclocked state, that
200x5 is a valid setting.

Say you change the CPU clock to 233MHz. You have to keep the HT bus
at under 1000MHz, so the nearest setting meeting the requirement is
233x4 = 932MHz. If you were to select 5x, you would be overclocking
the HT bus, which may work, or it may not work. The 7% loss in this
example, by running the bus at 932, would not be noticeable.

In fact, try running 3DMark while selecting the various values for
"Hyper Transport Frequency". That will tell you how critical it is
to get close to 1000MHz HT bus clock.

Paul
 
L

Leadfoot

Paul said:
"Leadfoot" said:
Any one know where there is a good guide that will explain what the Hyper
Transport settings do in relation to overclocking and memory timings

A8N-SLI deluxe needed 8 SATA ports and 3 PCI slots. Wanted premium but
have
Upside down Silverstone TJ-06 case

Athlon 64 3500+ venice retail BP @2700 11X245 1.55vdc P95 stable, not
stable
@11X250, Stock heatsink

2 X 512MB Kingston HyperX PC3500 running @158FSB @2.5-6-3-3??? Hyperx
3200
is ASUS Qualified bit not HyperX PC3500? Could use some advice on whether
there is a better choice in a memory upgrade to get better memory
performance

I've had this up and running since Sunday night and really like this
board
and processor. This A64 idles at 34C @1.55vdc and doesn't get much over
50C
with P95 Stress test set for FPU. Coolest processor I have ever owned

I tried for 3000MHZ with ClockGen for nVidia nForce4 but got a hard drive
pci.sys failure on reboot Good thing I have 7 hard drives on my box and
wasn't testing the primary windows system ;-)
Click to expand...

The Hypertransport bus, is the bus that connects the processor to
the single chip chipset. The bus is 16 bits wide up and 16 bits
wide down, clocks at 1000MHz, uses DDR, and in each direction that
is 1000x2x16/8 = 4GB/sec bandwidth. That bandwidth is used to support
the PCI-Express I/O for the video card (x16 = 4GB/sec up/down as well).
It also supports disk I/O and any other chipset peripheral bandwidth.

Now, you would think, based on that arithmetic, that the Hypertransport
is not fast enough. But a PCI-E x16 video card only needs about x4
to give decent performance, so the performance seen is not as sensitive
to the bus speed, as the arithmetic would suggest.

In the BIOS, you are offered [Auto, 1x, 2x, 3x, 4x, 5x] as options for
"Hyper Transport Frequency". These multipliers are multiplied by the
CPU clock. The nominal CPU clock is 200MHz. The nominal HT bus limit
for your board is 1000MHz. That says, in a non-overclocked state, that
200x5 is a valid setting.

Say you change the CPU clock to 233MHz. You have to keep the HT bus
at under 1000MHz, so the nearest setting meeting the requirement is
233x4 = 932MHz. If you were to select 5x, you would be overclocking
the HT bus, which may work, or it may not work. The 7% loss in this
example, by running the bus at 932, would not be noticeable.

In fact, try running 3DMark while selecting the various values for
"Hyper Transport Frequency". That will tell you how critical it is
to get close to 1000MHz HT bus clock.

Paul
Click to expand...

Thanks that is one of the better explanations I have gotton so far!!!
 
Top