P4 overclocking/memory settings questions

[Flightsim]

I am totally new to overclocking and just started to experiment with my 2.26GHz P4 yesterday. I?m using an Asus P4S533 with 512MB of Corsair XMS PC2700 memory. Right now I have my P4 set at 2.55GHz/150FSB with the voltage set around 1.5. I am using the default cooler and my idle temp is 40C. How far do you think I should be able to overclock my P4 using the default cooler and without stressing my CPU too much? My mobo won?t let me set the FSB beyond 166. Is that normal for the P4S533? I tried setting the FSB to 166 just a few minutes ago and the computer crashed, so I set it back to 150. Would I need heavy cooling or really high voltages to run at 166FSB? Also, the field where I change my FSB settings in the BIOS is labeled as CPU/PCI Frequency. What is the PCI frequency, and does it need to be locked at 33 or something? I also don?t understand most of the memory setting fields in the BIOS. In my BIOS, there are fields for: SDRAM CAS latency, SDRAM RAS to CAS delay, SDRAM RAS precharge time, SDRAM active time, and SDRAM command lead-off time. What do those fields mean and what should I set them at for my Corsair XMS PC2700? Should the memory settings be low when overclocking? Lastly, what is the CPU/memory frequency ratio and what values should I use for it? Sorry to ask such newbie questions, but I would greatly appreciate any help or advice.

 

[ChampionAtTufshop]

ok im pretty sure on your motherboard you dont have the ability to lock the pci frequency (bus) in spec, so when you are overclocking the cpu frequency, the pci frequency also increases at a ratio

what you want to try to do is get your cpu frequency to 166 bcause the other number should be 33mhz for pci (its normal mhz)
pci is for the soundcard, network card, etc that you plug into the motherboard in white slots under the videocard

the cpu memory ratio is the ratio between the cpu frequency and the ram frequency
if its 4:5 and cpu is 133mhz, ram is at 166mhz
if its 1:1 and cpu is 133, ram is at 133

 

[o1die]

Try 1.6 volts on the cpu, and 2.7 volts for the memory (using onboard jumper). Set the cpu/mem ratio at 4:5 and see how high you can run. Anything over 150 is good for this board. For memory timings, I use 2-3-6 and auto for ddram command rate. Some memory will run at a case setting of 2, but 2.5 is the norm. At case 2, my board won't boot with the generic memory I'm using. For agp, you can use 64 or 128. Agp fast writes doesn't seem to make any difference for my 8500LE. I tried setting it manually in the control panel (display settings), and it reverted back to the "no" setting, even when set in the bios. If system crashes with 4:5 ratio setting, set it to auto. For example with cpu at 133, memory will be 166 (4:5 = 133/166). So at 150, memory is running at about 187.5 ( x2 double pumped) or about 375 fsb. At 150 fsb, your pci is in the low 40's, which is ok for most devices. My modem gives me problems above 138. I'm only running my 1.8a at 2400 (133 at 1.6 volts) as this particular cpu doesn't overclock very well. I've tried on three different chipsets, and the p4s533 is the best so far. I'm thinking of getting the gigabyte 8sg667 (version 2 with voltage adjustments) or the albatron px845 pev pro.

 

[CrazySaint]

Assuming that your 2.26 is fairly recent (manufactured in the last month or two), then you have a reasonable chance of hitting 166FSB on 1.7v (as reported by Asus Probe, not what you set it to in the BIOS). I would suggest you set the mem ratio to 1:1, set the vcore to 1.65v (which should come pretty close to 1.7v), set the FSB to 166 and see if it will boot. Btw, it might help if you turned off things like USB and RAID if you have them.

 

[Flightsim]

At 150 fsb, your pci is in the low 40's, which is ok for most devices. My modem gives me problems above 138.

Well, at 150FSB, my pci was actually at 38, but I also started to encounter problems above 38. I did manage to get into windows at 157FSB(2.67GHZ), but my computer acted strange. Must be related to the pci frequency. I couldn't get 161FSB to boot at all, even at 1.65 CPU voltage. Why does the pci need to stay at 33? Is it harmful to run the pci frequency at 38 like I have it right now? Does overclocking shorten the lifespan of a CPU or harm it? Also, why would it help to turn off USB devices? My modem is a USB device and I couldn't live without it. I was able to set my memory at CAS2, 2-3-6, and auto for the command lead-off time. Thanks for all the info everyone.

 

[ChampionAtTufshop]

what is your temperature at 1.65v?
(run prime95 torture test for 15-20min, that should give you a pretty good idea of what your max load temp is)

put the fsb to 166 (this should make the pci to 33, unless you have other ratios to control the cpu/pci relation?)
cpu/ram ratio to 1:1
can you raise the ram voltage? (either through the bios itself or through jumpers on the motherboard? look in the manual)
ifyou can raise it to 2.7v

overclocking will decrease the lifespan, but the amount it depreciates is not easily predetermined. Going above 1.7v for the core on the northwoods has shown to cause rapid cpu death. Even with adequate cooling.

It is better to run pci devices as close to 33mhz as you can. most will survive and have no problems till about 38mhz, some are very sensitive and wont even go above 35or so. Its not harmful to run it over 33mhz in that it will cause death of the device in the very near future, but in due time it may be the cause of it failing.

 

[Flightsim]

put the fsb to 166 (this should make the pci to 33, unless you have other ratios to control the cpu/pci relation?)

If I were to put the FSB at 166, my pci setting would be at 42. As I increase the FSB, the PCI setting gradually increases too. I don't want to cause any problems, so I'm staying at 150FSB/38PCI. What do you think the other ratios that control the cpu/pci relation could be??? If my cpu/mem ratio is set at auto, does that mean it is probably running at 1:1? I don't think I can change the memory voltage within my BIOS, but why would this help? Is it potentially dangerous for the memory like going above 1.7v is for a P4?

 

[CrazySaint]

Originally posted by: Flightsim

put the fsb to 166 (this should make the pci to 33, unless you have other ratios to control the cpu/pci relation?)

If I were to put the FSB at 166, my pci setting would be at 42. As I increase the FSB, the PCI setting gradually increases too.

That's true up to 165, but at 166 the 5/1 divider kicks in putting everything back where it should be.