Overclocking memory?

[Benjamin]

How do I overclock my memory? My motherboard lets me set the speed, so i set it to 333MHz (I have DDR266),but when I boot, it beeps then goes back to the default settings. Do I have to have a certain type of memory that is overclockable?

[iMc]

If you have DDR266, then try to run it at 333Mhz is going to to much of a push. best to overclock a little by little.

[Benjamin]

You mean memory can be different speeds other than 266/333/400? Shows how much I know lol.

[iMc]

yeh if u increase ur fsb to say 170 ur memory will run at 340 (2x fsb). Its always a good idea to run fsb in sync with mem so if ur like me and got DDR400 its best to wack the fsb up to 200 (200x2=400) and then reduce the multiplier so that u dont OC the cpu. unless of course ur tryin to OC the cpu!

[Benjamin]

yeh if u increase ur fsb to say 170 ur memory will run at 340 (2x fsb). Its always a good idea to run fsb in sync with mem so if ur like me and got DDR400 its best to wack the fsb up to 200 (200x2=400) and then reduce the multiplier so that u dont OC the cpu. unless of course ur tryin to OC the cpu!

Yeah corresponding logic is the most efficient.

[iMc]

lol. anyway u ok with ur problems now!

[SilentDeath]

overclocking fsb will also do more things:
overclock the mobo - more chipset votlage, and or better coolig may be needed.
push the pci and agp bus's out of spec - random lockups maybe
overclock cpu - if cpu is unlocked, decreasing multi would fix that.
overclock the mem far enuf to prevent booting - more vdimm voltage or less agressive timings could help. you might need to reset cmos or hold insert on next boot to get it to post again.

when overclocking mem (fsb) it is important to run memtest86 before booting to any installed OS to prevent it from corupting. test 5 is most important, the rest often wont find any errors.

[Benjamin]

I tried putting my FSB and memory at 140MHz (since its x2 no?) and it didn't let me boot...I just got the 'beeeep' and it went back to it's default settings. Does this mean I can't overclock my memory at all?

[SilentDeath]

run the mem at stock and do a test of memtest86. it may even be unable to run at stock without errors if your getting probs that quick. also try upping the Vdimm voltage and or changing the timings, should help lots
it could be the cpu or mobo causing it btw.

[Benjamin]

run the mem at stock and do a test of memtest86. it may even be unable to run at stock without errors if your getting probs that quick. also try upping the Vdimm voltage and or changing the timings, should help lots
it could be the cpu or mobo causing it btw.

I believe I can up the voltage to 1.7 V....I'll have to check. I will do that memory test.

[Benjamin]

And how long does this test usually take? Last time I checked (my comp is downstairs) it was at 8 minutes and only 20% complete.

[SilentDeath]

1.7 is ***NOT*** Vdimm! may be chipset votlage (Vdd) or Vcore (usally upto 1.85v)
Vdimm, for DDR ram, will be 2.5 for JEDEC (standard) 2.6 is normal, and most mobos will allow upto 2.8. most mobos wont do higher becuase its not usually needed, and due to msot of them using the 3.3v rail for powering it, and usual 0.3v drop due to variances, its not wise to have it higher, and it wouldnt e good for ram either...

first time you run it do tests 1/2/3 in order first, then when it starts 4, push C, 2, 5, 5, ENTER, 0. that will skip test 4 and loop test 5 continually. test1-3 are only usefull the first time, they only really pick up errors from damaged components, stuff runing out of spec, usually wont ever error on those tests, unless its very bad. tests 6 and 7 are like 5 but take longer, if 5 gets errors sometimes or your not sure, do 6 and 7 aswell.
test5 doesnt take tooo long, one of the quickest imo.. run it about 3 times as most mem wont get errors untill it gets warm

[Benjamin]

Vdimm? I'm talking about my memory...it says memory voltage and i can select 1.6 or 1.7 I think. ill have to check when the test is finished.

[SilentDeath]

vdimm is mem.
ddr ram uses 2.5v (jedec standard), 2.6 is normal default on recent mobos, and 2.7 is the next one up. im quite sure no ddr ram would run at 1.7v.

[Benjamin]

My bad lol. You were right...AGP voltage is 1.6 and 1.7. I tried uping the voltage and my memory and it still didnt work
I have a Shuttle AN35N Ultra

[Rod911]

By the look of your sig, it looks like you've got a pretty rare 2600+ there. If it is in fact a TbredB 2600+ running off a 266Mhz, that means you've got a 16x multiplier. If you were unsuccessful at running 140Mhz (280Mhz DDR), it might be because you might not have enough voltage running through your CPU (140*16=2.2Ghz...3200+ territory). Generally speaking though, you should be able to get to at least 140 with cheap and crappy 133 RAM if you up the vDIMM (up to 2.8v is safe for day to day use) and relax the timings.

Just take note that there has been three 2600+ models:
- TbredB 2600+ 333Mhz (12.5*166)
- TbredB 2600+ 266Mhz (16*133)
- Barton 2600+ 333Mhz (11.5*166)

If I'm mistaken about your CPU, can you please note which 2600+ do you have out of the ones listed above?