Improving memory timings

Kei · 21 Mar 2013 at 18:50

Had my phenom II x4 955 overclocked to 3.7GHz for nearly 4 years with little trouble. I believe I have hit the limit of my C2 stepping at this level, however, I've never really spent much time on the memory timings and FSB side of things. I have a pair of 4gb kingston hyperx genesis modules and a pair of 2GB corsair dominator modules. Here are the present settings that I run. (if BIOS shots are needed, I'll have to restart to get some) Memory voltage is set to 1.65V.

Full system spec is in my project thread. Any ideas on where potential improvements could be made?

Kei · 22 Mar 2013 at 15:23

If it helps at all, here are the bios settings. I've shifted over to SPD settings on the timings @ 1333MHz and CR back to 1T. (thought it had to be 2T when using more than 2 modules) It seems to be working ok so far though.

What i don't know is what settings will make the biggest differences and whether it is better to have a higher FSB and looser timings or slightly lower FSB and tighter timings.

medseven · 23 Mar 2013 at 00:36

I hear that the memory speed is so much more noticeable than the timings. Especially in games.

I've been playing around with my FSB and Memory speeds along with the timings these past few days, and every test I did supported this.

Both the links to the memory kits you have show the memory is designed to run at 1600mhz so you could get a lot more out of them.

In the bios pic you got there, there's a setting Memory Clock [x6.66] can you increase this at all? Also what kit is that?

medseven · 23 Mar 2013 at 15:59

looking at the 4GB kingston HyperX genesis modules they have an XMP profile of 800mhz (1600mhz) @ 9-9-9-27-36 @ 1.65volts.

Although not an Intel board with XMP profiles this gives you a good idea what your memory can run at.

I would try a FSB of 240mhz, with memory multiplyer at x6.66 should give you speeds of 1598mhz. I would try this with the timing's 9-9-9-27-36 @1.65volts like the XMP profile.

With your CPU stable at 3.7ghz and this FSB at 240mhz a CPU mutliplyer of 15.5. 240x15.5 = 3720mhz.

With the HT link you then will probably have the options of 1920mhz and 2160mhz. I would go slightly below to start.

NB you should have the same options and also 2400mhz. I would choose this as I see your NB has been stable at that already.

SO...

FSB 240mhz
CPU Multiplyer X 15.5 = 3720mhz
Memory Multiplyer x 6.66 = 1598mhz
Timings 9-9-9-27-36 @ 1.65volts
HT Link 1920mhz
NB 2400mhz

This gives most your setup the same speeds as you have been running stable at but a lot faster speed on the memory, which is also the setting they are sold to run at. Give it a try as opposed to tightening the timings like your doing, run a few bench's with what you got now and this and see!

Kei · 23 Mar 2013 at 16:27

Cheers for the information, very detailed and helpful. The days of unlocked multipliers has made me a bit lazy on the overclocking front. I'll give these settings a go when I get home.

medseven · 23 Mar 2013 at 18:26

No worries, been playing with memory quite a bit last few days myself. One quick and easy tool I use to see what read / write / copy speeds im getting from the different speed vs timing setting's I've been trying is the Aida64 free version bench...

Kei · 23 Mar 2013 at 19:42

It seemed to be going ok for a few minutes and then it hit a spontaneous restart during prime testing. I've gone back to my original settings and noticed that it still was stable during prime as i got a bluescreen again. I had been decreasing my Vcore and was down to +0.05V (from +0.125) in an effort to help lower my temperatures. It seems my "ye olde" C2 stepping likes some volts. I'm testing it at +0.100 now. Once i've got it stable I'll retry your settings.

Where do you get the free version of aida? (all i can find is the trial version)

medseven · 23 Mar 2013 at 20:37

Ah yeah its the 30 day Trail ive been using while playing with my ram, I thought the 30days would give me more than enough time to play around with settings and settle on some.

You say your CPU has been running at 3.7ghz no worries and the settings here ask it to run at pretty much the same, just a little more. The thing is it always tends to be a bit more when in windows than it says exactly in the bios.

For example your original settings were FSB of 200 multiplier of 18.5, exactly this is 3.7ghz in the bios but then in windows you get 3717mhz according to your CPUz pic. The settings I offered make 3720 mhz in the bios but when booted in to window's could be near 3.8ghz, and it might be the difference here that is pushing the CPU over. Especially if you took the time before to find the high-max stable of your cpu.

Few things I would try is perhaps the same settings as above, but first maybe with a FSB of 236mhz and not 240mhz and then maybe 238.

Also when it comes to Vcore and such does your bios have a setting where you can enter the manual voltage as opposed to offset like +0.05 or 0.1 as I find it easier to see when testing settings to know exactly what voltage is being pumped to the CPU the whole time!

Kei · 23 Mar 2013 at 21:09

I've upped the Vcore back to 1.45V (+0.1 offset) and that seems to have stabilised it. (obviously i'd lowered it too far) It seems to be ok with the settings now. I'm using the trial of AIDA but it covers a lot of the bench figures with "TRIAL VERSION".

Kei · 31 Mar 2013 at 19:37

Had some more time to fiddle about with it today and found that i can take the FSB all the way up to 275 and it's still stable. Question is, is it better to have the FSB higher and the memory slightly lower with tighter timings? I can't seem to get the NB frequency much higher, though it might be ok in the middle ground between 2500 & 2600. The system won't post at an FSB of 280 or an NB of 2750. (even with some extra volts)