NF7-S "CPU Interface"-- on or off?

[Fishface]

You guys who are clocking your memory very fast...

Do you have "CPU Interface" enabled or disabled?
With Corsair PC3500 and a 2500+, I can run no faster
than 212 with it enabled. When I turn it off, the memory bandwidth as measured by SiSoft Sandra suffers greatly. But at 230 MHz, with it disabled, the measured bandwidth is not much greater than at 212 MHz with it enabled and with memory timings held constant.

What enabling "CPU Interface" do? Is it similar to a PAT or GAT thing? I notice there is no "Command Rate" setting to tweak on these boards...

 

[Chip]

"Fishface" <?> wrote:

You guys who are clocking your memory very fast...

Do you have "CPU Interface" enabled or disabled?
With Corsair PC3500 and a 2500+, I can run no faster
than 212 with it enabled. When I turn it off, the memory bandwidth as measured by SiSoft Sandra suffers greatly. But at 230 MHz, with it disabled, the measured bandwidth is not much greater than at 212 MHz with it enabled and with memory timings held constant.

What enabling "CPU Interface" do? Is it similar to a PAT or GAT thing? I notice there is no "Command Rate" setting ...

Basically it tightens up the timings to which you don't have access in the bios. For example it sets Command Rate to 1T. Lots of brands of memory have trouble with 1T Command Rate, although I would have thought your Corsair would be OK. What voltage are you using? My OCZ PC3500 runs up to 228 OK at 2.7v with CPU Interface enabled. I would have thought that Corsair would be similar?

Chip.

 

[rms]

228 OK at 2.7v with CPU Interface enabled.

230 on nf7-s v2, enabled. My impression was disabling it *lowered* the max fsb on my board, but I'll try again soon. Geil.

rms

 

[Fishface]

Chip wrote:

Basically it tightens up the timings to which you don't have access in the bios. For example it sets Command Rate to 1T. Lots of brands of memory have trouble with 1T Command Rate, although I would have thought your Corsair would be OK. What voltage are you using?

It's cranked to 2.9v, at 2-2-3-6. I tried raising the timings , but it still wouldn't run faster with "CPU Interface" enabled. I haven't extensively tested with "CPU Interface" disabled though, just a half-hour of Prime95 and no Memtest86 as of yet. I'm trying to maximize bandwidth.

My OCZ PC3500 runs up to 228 OK at 2.7v with CPU Interface enabled. I would have thought that Corsair would be similar?

Awesome! What timings?

 

[Chip]

"Fishface" <?> wrote:

Chip wrote:

Basically it tightens up the timings to which you don't have access in
the bios. For example it sets Command Rate to 1T. Lots of brands
of memory have trouble with 1T Command Rate, although I would
have thought your Corsair would be OK. What voltage are you using?

It's cranked to 2.9v, at 2-2-3-6. I tried raising the timings , but it still wouldn't run faster with "CPU Interface" enabled. I haven't extensively tested with "CPU Interface" disabled though, just a half-hour of Prime95 and no Memtest86 as of yet. I'm trying to maximize bandwidth.

My OCZ PC3500 runs up to 228 OK at 2.7v with CPU Interface
enabled. I would have thought that Corsair would be similar?

Awesome! What timings?

It will run 6-3-2 cas2 perfectly fine, but 7-3-3 cas2 is the same speed so I run 7-3-3. I see people running 5-2-2 cas2 with Corsair though.

Chip.

 

[BigBadger]

What revision of Corsair XMS do you have?...The Rev 1.1 used BH-5 chips whereas the later Revs used BH-5 chips which don't perform quite so well at tight timings.

I'm running XMS3500 rev1.1 at 225FSB no problem CAS 2-2-2-7

 

[Fishface]

BigBadger wrote:

What revision of Corsair XMS do you have?...The Rev 1.1 used BH-5 chips whereas the later Revs used BH-5 chips which don't perform quite so well at tight timings.

They sez 1.1. I guess the second BH-5 should read CH-5?