ABit IS7 P4 2.4C Overclocking

[FPSguy]

Hi all. So I finally overclocked the P4 2.4C this weekend. It was pretty easy. It's currently at 250MHz bus (3 GHz), with the memory on a 5:4 ratio and the VCore at 1.65. Stock cooling. The CPU stays around 47 degrees celcius. I am pretty happy with it as is, but if there are some easy tweaks to improve it while maintaining stability and safety I might as well try them. Rather than do the usual trial-and-error, I thought I would post and see what people suggest. Here are things I would try if I were to do a trial-and-error session. I am curious about people's thoughts as to which of these things are likely to bring success in terms of speeding up the PC while maintaining stability and not burning anything out, and whether there are other things I should try.

1. I would love to move the VCore down and thus (hopefully) lower the CPU temp a bit. Do you think it will be stable? (It was not stable at stock VCore -- 1.525 volts -- and I didn't try any other voltages besides 1.65)
2. I tried 260MHz FSB and got errors. The memory (2 x 256MB Kingston HyperX PC3700, 2.6V variety) should be capable of 270MHz FSB on a 5:4 ratio. I think I bumped up the VCore to 1.7 and that didn't help. I assume it's a BIOS setting that is preventing the higher FSB. I have hyperthreading on (how do you turn it off, and do I want to?) and have all GAT settings on AUTO (is it worth changing them to get a higher FSB [a lot of people recommend "auto, normal, auto, disabled, disabled"], or is it faster to have them on auto with a slightly lower FSB?).
3. I left CPU strap on AUTO. I have read that setting it to 667 increases memory bandwidth for some reason. Do you think I should do that?
4. Is there anything else you suggest I try?

Obviously I can try these things and run multiple benchmarking sessions and see what is fastest, but I figure so many people have this setup that I shouldn't recreate the wheel.

My full system configuration is available in my System Rigs link below. I am talking about the PC creatively named "ABit IS7 Machine".

TIA for your input!

 

[sman789]

try 5:4, 250fsb, stock vcore..up the vdimm to your liking(mines at 2.8)
strap to 800, leave HT on.....set the GATs to those recommended settings, manually set its timings to its advertised ones


stability test it....then up the fsb speed by 5's...when it gets unstable try upping the vcore now

 

[FPSguy]

I think I have tried that. The system is very stable at 250 MHz FSB. When I try 260MHz, though, it restarts at some point during 3dMark03. The memory (2 x HyperX PC3500 256MB) should be able to do 270 FSB on a 5:4 ratio.

Here is my setup:
IS7 (BIOS 16)
P4 2.4C
5:4 memory
VCore is 1.575 (also tried 1.65)
VDIMM is 2.7
Intel stock cooling (CPU temp = 45 degrees)
GAT=AUTO, NORMAL, AUTO, DISABLED, DISABLED
Memory Timings: 3-3-3-8
Hyperthreading is on
Strap=By CPU (also tried 800; also tried 667)
PCI/AGP - Fixed

I am thinking that it's the memory timings and I need to ratchet GAT down. Does anyone have a similar system and have any ideas about what is holding the system back?

TIA for your input!

 

[Salamandar]

I have a system so close to you, why don't you try to raise the VDIMM to 2.8 !

 

[FPSguy]

Originally posted by: Salamandar
I have a system so close to you, why don't you try to raise the VDIMM to 2.8 !

Have you tried that and did it work for you? I am reluctant to push the memory voltage to the highest setting (2.8V) in this situation because the memory is underclocked at 260 FSB / 5:4 ratio. The memory can do 217 MHz but at 260 FSB / 5:4 ratio the memory is only doing 208 MHz. Thus, it shouldn't require any extra voltage for the memory to handle this. (of course, just because it shouldn't be required doesn't mean that the extra voltage isn't the missing key ...)

 

[orion7144]

Originally posted by: FPSguy

Originally posted by: Salamandar
I have a system so close to you, why don't you try to raise the VDIMM to 2.8 !

Have you tried that and did it work for you? I am reluctant to push the memory voltage to the highest setting (2.8V) in this situation because the memory is <STRONG>underclocked</STRONG> at 260 FSB / 5:4 ratio. The memory can do 217 MHz but at 260 FSB / 5:4 ratio the memory is only doing 208 MHz. Thus, it shouldn't require any extra voltage for the memory to handle this. (of course, just because it shouldn't be required doesn't mean that the extra voltage isn't the missing key ...)

Just set the memory to 2.8 and forget about it. The memory is rated at 2.6-2.9 volts anyway. The problem you are having with the 5:4 ratio is comon among all 865/875 boards and certain memory. The Kingston suff I tried did not work with the multipliers at all. However the OCZ works fine. If you check out the IS7 stickied thread in the MB section you could find alot of info.

As for your Vcore I would suggest leaving it at 1.55, up the Vdimm to 2.8 GAT Auto/AUTO/AUTO/DISABLED/DISABLED. Set timings to SPD and go from there.

 

[FPSguy]

Okay. Thanks. I will give the 2.8 VDIMM a shot.

For what it's worth, according to this page on the Kingston website the specification for HyperX PC3500 is 2.4 - 2.8 volts. Since 2.8 is within the official specification I think (hope ...) it should be safe.

 

[orion7144]

Originally posted by: FPSguy
Okay. Thanks. I will give the 2.8 VDIMM a shot.

For what it's worth, according to <a class=ftalternatingbarlinklarge href="http://www.valueram.com/datasheets/KHX3500_256.pdf" target=blank>this page on the Kingston website</A> the specification for HyperX PC3500 is 2.4 - 2.8 volts. Since 2.8 is within the official specification I think (hope ...) it should be safe.

You will be fine. I got my specs confused with a different version. Anyway you are still withing their limits and the warranty would still have to be honored. Shoot you can't go any higher on that board anyway.

 

[FPSguy]

Originally posted by: orion7144
Just set the memory to 2.8 and forget about it. The memory is rated at 2.6-2.9 volts anyway. The problem you are having with the 5:4 ratio is comon among all 865/875 boards and certain memory. The Kingston suff I tried did not work with the multipliers at all. However the OCZ works fine. If you check out the IS7 stickied thread in the MB section you could find alot of info. As for your Vcore I would suggest leaving it at 1.55, up the Vdimm to 2.8 GAT Auto/AUTO/AUTO/DISABLED/DISABLED. Set timings to SPD and go from there.

Okay, here is what I tried last night, which leads me to believe that my cheapie power supply (additional specs for it here) may be the problem. First, I did everything orion7144 said, and upped the bus to 260. 3dMark03 ran for a few minutes and then the PC rebooted. Slowly I upped the VCORE with those settings. That didn't matter -- 3dMark03 would always reboot. Then I put the VCORE back at 1.575 (the last known stable setting with the FSB at 250) and set the memory divider to 3:2 with a 260 FSB. So now the memory is at 173 and well underclocked. I switch to Prime95. Turns out, it won't go two minutes before giving an error. Then I go back to my "stable" setting of 250 FSB, 5:4 memory ratio ("stable" because I can run 3dMark as much as I care to -- which is only two or three times -- and I don't get any errors). Running my hardware monitor I see that the 3.3V rail is looking kind of low (around 3.18) and during Prime95 I get several warnings from the monitoring software as the 3.3V rail gets down around the low limit of 3.10. Meanwhile, although I am not getting warnings about the 12V rail, the VCore is fluctuating between 1.52 and 1.58 or so during Prime.

So, is it the power supply, or is it something else? I would appreciate any insight anyone can offer (and if it is the power supply, recommendations for replacements would be great -- how about the Antec SL450?).

 

[orion7144]

Originally posted by: FPSguy

Originally posted by: orion7144
Just set the memory to 2.8 and forget about it. The memory is rated at 2.6-2.9 volts anyway. The problem you are having with the 5:4 ratio is comon among all 865/875 boards and certain memory. The Kingston suff I tried did not work with the multipliers at all. However the OCZ works fine. If you check out the IS7 stickied thread in the MB section you could find alot of info. As for your Vcore I would suggest leaving it at 1.55, up the Vdimm to 2.8 GAT Auto/AUTO/AUTO/DISABLED/DISABLED. Set timings to SPD and go from there.

Okay, here is what I tried last night, which leads me to believe that <a class=ftalternatingbarlinklarge href="http://www.3btech.net/repcpotise45.html" target=blank>my cheapie power supply</A> (<a class=ftalternatingbarlinklarge href="http://www.shentech.com/repcpo45atve.html" target=blank>additional specs for it here</A>) may be the problem. First, I did everything orion7144 said, and upped the bus to 260. 3dMark03 ran for a few minutes and then the PC rebooted. Slowly I upped the VCORE with those settings. That didn't matter -- 3dMark03 would always reboot. Then I put the VCORE back at 1.575 (the last known stable setting with the FSB at 250) and set the memory divider to 3:2 with a 260 FSB. So now the memory is at 173 and well underclocked. I switch to Prime95. Turns out, it won't go two minutes before giving an error. Then I go back to my "stable" setting of 250 FSB, 5:4 memory ratio ("stable" because I can run 3dMark as much as I care to -- which is only two or three times -- and I don't get any errors). Running my hardware monitor I see that the 3.3V rail is looking kind of low (around 3.18) and during Prime95 I get several warnings from the monitoring software as the 3.3V rail gets down around the low limit of 3.10. Meanwhile, although I am not getting warnings about the 12V rail, the VCore is fluctuating between 1.52 and 1.58 or so during Prime.

So, is it the power supply, or is it something else? I would appreciate any insight anyone can offer (and if it is the power supply, recommendations for replacements would be great -- how about the Antec SL450?).

Good choice if yu decide to get a new PSU. I had a PS that was fluctuating like that (sometimes worse) and I replaced it with the Antec True Control 550 and my Votages are rock stable now. That could be your problem but it could also be your RAM. Did you try with just one stick? Like I said these chipsets do not like certain memory while using any of the ratios but will work at or above their spec 1:1. I know it makes no sense that memory that will do 250FSB 1:1 will not run 250 5:4. That is why I went through several different combinations of memory till I found the one's that work. And for these boards I like the OCZ EL and Gold memory.

What is the highest that memory will do 1:1? Have you tried it at 250 1:1.

 

[FPSguy]

I have been playing around with this some more and I am stumped as to whether my problem is the CPU, the memory, the motherboard's problems with memory dividers, the North Bridge, or something else. I did get a new power supply (an Antec TrueBlue 480 -- it's very stable). With VDIMM at 2.8 and VCore at 1.575, the machine is very stable at 250 FSB / 5:4 memory divider. When I tried a 255 FSB it could not run 3DMark 2001SE without crashing. When I upped the VCore to 1.625, though, at long last it ran stable above 250 FSB. Then I tried 260 FSB. I had to up the VCore to 1.65 for that to be stable. I tried 265 FSB / 1.675 VCore, but that was not stable. I really wanted to get the machine stable at 270 FSB with a reasonable VCore, but so far that is not looking good.

I also tried 220 FSB on a 1:1 ratio, but the machine would not boot properly with the memory at that speed.

I have GAT on auto-normal-auto-disabled-disabled, with my Kingston HyperX 3500 set manually to 2-7-3-3 timings (I also tried 2.5-8-3-3).

Do I have a weak (for a 2.4C) overclocking chip, or are there some things I can do to improve the overclock?

 

[Duvie]

usualluy when a cpu hits the wall like that without a tapering down with higher vcore it is a sign (IMO) of other limitations....

OK here is one you may not have tried....What bios are you running??? Have you tried the latest as listed on their site??? The reason I ask is early bioses on the abit mobos had problems getting over 255fsb....I think may sound like yours and I think the bios resolve some timing issues....

The 3.3v rail supplies the vdimm for you memory so it was good to be cautious about that...

 

[FPSguy]

I have BIOS v. 16 (the latest one per this page on the ABit site). Any other thoughts for how I can "break through the wall" with this processor? I hate to keep buying parts (especially expensive memory, which probably would be worth trying). The only memory I have that I could swap out would be some Crucial PC2700 (which I have actually gotten to run at 190MHz on another machine, so it would probably run on the IS7 using a 3:2 divider). I wish there were a quick fix ...

 

[Duvie]

I thought there was a bios version 17 (may just be for IC7) but I could be wrong...Contact elite members Thugsrook or Oldfart and see if they know of a better beta version bios or if you have some setting enabled or disabled in the bios that may be holding you back. No one has probably around these parts thoroughly messed with about every setting as Thugsrook....

 

[Duvie]

Also up the vagp to 1.7v and the vdimm to 2.7-2.8v.....Also try seeing if the northbridge chipset needs either better cooling or to be relapped with some artic silver. The stock version is often unsufficient and the goop they use is not as good....May try placng a large fan right at it...I never trust the temp readings on the northbridges so even if the temp says 30c or something try it...

 

[Razzd]

Can you guys furnish me with some of the detailed S-Spec/Batch(es) of the 2.4Cs that successfully o/cs to 3.0Ghz and above on default voltage? Thanks.