FSB:Mem Ratios

Adeptus Titanicus

Having googled a bit I understand the principles behind the FSB:Mem clockspeed ratio, but I can't seem to change it when O/Cing.

have been ramping up the FSB, and am now at 233x15, but the ratio is automatically setting to 3:2! In the BIOS there are choices for DRAM frequencies of Auto, 266, 333 and 400. What next? If the 3700 is supposed to run at 233 (466 Dual) where do I go from here? From an earlier test at an FSB of 220, also with a ratio of 3:2 I dropped a few points from stock speeds in 3DMark 2001 and 2003...

It's probably something simple that I have missed, but maybe I need a formula

EDIT:

Actually, add to that a question on voltages. I have the BIOS handligng voltages automatically, The vCore never seems to go above 1.58, and I have no idea what the RAM is at. All the overclocking guides I;ve read mention stepping up the voltages slowly if there is instability. Should I fix them to a value just in case?

It's great to be surrounded (albeit virtually) by brains

Sir Random

Set the Dram Frequency to 400 for 1:1, 333 for 5:4 and 266 for 3:2

Adeptus Titanicus

Man... /me kicks himself

I guess I was thinking too literally. I expected something equating to PC3700. So in this case, 1:1 is defined in relation to the stock FSB speed? Makes sense.

I duly set it to 400 with the FSB at 233x15, so had a nice simple O/C of 3.5GHz at 1:1 running at 2.5,4,4,8. Kept the 9800 at stock for this. Ran 3DMark and got the following.

Test Stock/Overclock 1
2001 17400/18696
2003 5787/5897

Will OC the 9800 and run again, although it gets pretty hot. GFX at 66 degrees while running 2001... :dunno: But CPU maxed at 47 with the zalman up full..

I still wonder about the voltages though. Is it ok to let these go auto?


Thanks again Sir Random, you should get a knighthood... oh wait......

Adeptus Titanicus

Oh yeah, the memory using SPD was set to 2.5,4,4,8, but it is rated at 2.5,3,3,7. I guess I should go and set it manually?

OfflerCrocGod

Originally posted by Adeptus
Oh yeah, the memory using SPD was set to 2.5,4,4,8, but it is rated at 2.5,3,3,7. I guess I should go and set it manually?

Yes or you could try loosening the timings and setting the RAM to 2.0 CAS latency; that will give more of a performance boost then tighter timings.

Adeptus Titanicus

Yeah, I had been thinking that. It seems pretty solid at the moment (running a torture test). If it doesn't like it at CAS 2 I assume it will just belly up at some point?

I'm still wondering about voltages though and whether to set them manually or let the system decide. I think the P4C800 is limited to 2.85 on the RAM, and this stuff is covered up to 3, so no worries there.

Thanks!

Sir Random

Yeah, give the ram 2.85v and be done with it.
You shouldn't need to raise the vcore unless you're getting prime95 errors that aren't ram related.

jk2001

hiya, just being curious... which RAM do you have in your system? Seems to be top stuff to be covered up to 3v.

jayo

jk2001

DOH, got it.... sorry for wasting your time

Adeptus Titanicus

lol, no worries No time wasted here!

Woden

do you have the lastest version of the bios perhaps the newest one supports higher vdimm. i read an article on xbit labs about how ocz have managed to tighten the timings on high frequency ram to 2.5 however i think they where supporting the asus board mainly as it could supply the voltages required.

i'll look for the article it was only today i think

data

http://www.xbitlabs.com/news/memory/display/20040412160333.html

bah heres the article but the ram only needs to be run at 2.85v as well

unkel

My OCZ PC4200 runs at stock 2.5,4,4,7 @ 2.6V, guaranteed to 3.0V

Big deal if they get PC4400 at 2.5,4,4,8 and have to use 2.85V :rolleyes:

OCZ recommends using P4C800 and P4C800-E mainboards with its new set of dual-channel PC4400 Limited Edition Gold EL DDR memory modules.

WTF? The BIOS on these mobo's only allow vdimm to go to 2.85V, so no overclock possible. Have they lost all faith in there memory all of a sudden

Woden

well it is a big deal if they are cutting off a chunk of there market because there motherboards currently can't supply the required voltage to give the performance that ocz can give.

overclocks are still possible even if you can't up the vdimm anymore if you needed to lash up the frequency even more then that the timings could still be loosened again

data

Adeptus Titanicus

Originally posted by Dataisgod
do you have the lastest version of the bios perhaps the newest one supports higher vdimm. i read an article on xbit labs about how ocz have managed to tighten the timings on high frequency ram to 2.5 however i think they where supporting the asus board mainly as it could supply the voltages required.

i'll look for the article it was only today i think

data

http://www.xbitlabs.com/news/memory/display/20040412160333.html

bah heres the article but the ram only needs to be run at 2.85v as well

Yeah, 2.85 has been plenty for me I think. I've actually been running it at 2.6, and when I have been getting instbaility and upped the voltage it didn't help.

Re the PC4400 RAM, I'm sure memory that requires 2.85 can be clocked higher without requiring more volts. What's the average high-end vDIMM that mobo's can support anyway?

unkel

Originally posted by Dataisgod
well it is a big deal if they are cutting off a chunk of there market because there motherboards currently can't supply the required voltage to give the performance that ocz can give.

Don't understand what you mean data? Most motherboards would surely be able to supply more than 2.85V to the ram?

Originally posted by Adeptus
What's the average high-end vDIMM that mobo's can support anyway?

My AI7 goes to 3.2V

Woden

yes i though most motherboards would supply a lot more voltage to the ram i presumed the reason why ocz where backing asus on this one was because it was one of the few motherboard that could supply the vdimm the chips required, i think the current revision of my abit bios only does 2.8 or 2.9 more 2.8 though i'm thinking however a later bios revision make have changed that

data

unkel

Originally posted by Dataisgod
i think the current revision of my abit bios only does 2.8 or 2.9 more 2.8 though i'm thinking however a later bios revision make have changed that

do you mean it steps per 0.1V, so it does either 2.8 OR 2.9 and not 2.85?

My AI7 steps this way, so it won't do 2.85, but surely in that case you just use 2.90? Shouldn't be an issue, should it?

Woden

mine only steps as 0.1 and may only go up to 2.8v i can't recall but again i haven't a clue what the latest bios updates have done as i haven't needed them

unkel

Ah I see. You more sensible than me. Usually check abit site about once every one or two months for BIOS update and apply it. If I don't like it, I'll change back (never happened over the years)