I7 950 OC and RAM speed

[killafaz]

Hi guys,

I'm new to the forum but read the site regularly. I have a quick question about my CPU multiplier in my OC and my RAM timings.

I've just built a new rig last week and got to work overclocking it (see sig for full rig). After playing around and tuning it a bit, I've got my CPU i7 950 to 4.2Ghz at 23x multiplier and 183 Bus speed. This causes my Corsair XMS3 RAM to run at about 1440Mhz if I recall correctly. I would like it to run at the rated 1600Mhz. My current timings are 8-8-8-24 with a voltage of 1.65 all set manually.

My question is, if I drop my multiplier and raise my bus speed to get higher speed from my RAM, will that negatively affect the performance of my PC/CPU, or does the higher multiplier not matter too much? I'm a bit of a noob when it comes to overclocking and only know the basics, so any help would be appreciated.

I'd like to point out my system is 100% stable with it's current settings and clock speeds. That includes 12 hours prime95, any game I can throw at it, 3D Mark Vantage etc. I just want to try and get the most out of my RAM with a little bit more work. I'm sure there's loads of things I could do do tune my PC up more, but I'm not that advanced. Just wanted to know if dropping the multiplier is a big deal to get a higher bus speed for faster RAM, or maybe should I drop the timings and keep the RAM at it's current speed? If you need more info please ask.

Thanks in advance.

 

[sportsfanboy]

You can drop the multiplier and raise the base clock. With a relatively high multiplier it shouldn't be too difficult to dial in. Obviously the higher the base clock gets the harder it will be to run stable.

Personally I would leave it where it is if you have it nice and stable, and start lowering memory timings. You will most likely be able to run 7-7-7-21 or lower. As you probably know, your current speed with lower timings against stock speed with higher timings will result in about the same performance.

 

[killafaz]

Thanks sportsfanboy. Sounds like dropping my memory timings is the best way forward then. When I do this as it's not something I've done before, do I need to do it in a particular order? Or can I just drop all the timings together and go from there? Whats the best way to test the new timings for stability and what are the signs of the timings not being stable ie blue screens or crashes etc? Thanks for your help.

 

[sportsfanboy]

With main timings you can usually set all 4 then start testing. I like to use memtest as a boot disk first, then prime95 blend, make sure "round off checking" is checked or you wont see the errors if any. After your sure the cpu is stable, that's very important as you wont know if it's your ram or cpu if you get errors. If memtest and blend check out try some gaming and see how that goes.

There are some things the computer might do if your not setup correctly.

1) Hanging on startup

2) Blue Screen on start up

3) Freezing in programs/games that wasn't present before

4) Some weird stuff, maybe the mouse is acting a little off or just the system feels different.

5) Crashes

 

[killafaz]

Nice one mate. Thanks for that. So general overclocking instability symptoms are what I need to look out for. When I get home I'll try the 7-7-7-21 timings, run a memtest, then prime95 blend. If that's all good to go, I'll crack open the games and go from there. Do I need to run prime95 blend for a certain period of time, or does it run through a generic test?

With regards to if I do get errors/crashes etc, do I just crank the timings up by one i.e 7-7-7-21 isn't stable so put it up to 8-8-8-22? Or can I get away with just putting up one timing such as 8-7-7-21? Sorry for all the questions mate, as you can tell, I'm fairly inexperienced with overclocking, particularly RAM. All your help is much appreciated.

Thanks again.

 

[sportsfanboy]

Memtest will have progress to watch, I try to run it twice in a row(without stopping the test) to make sure. I use the first as an idea and a warm up, as computer parts tend to act differently when warm or hot as compared to cold. For blend I would run it for a half hour or so, if no errors move on to some gaming and see how that goes. If you pass that go back to blend and let it run for at least two hours. Make sure your cpu temps stay within specs because blend still heats the cpu nicely.

General rule of thumb is the first 3 timings then add them to get the 4th. That's a very rough guide but you get the idea. So if 7-7-7-21 fails(I don't expect it will) you can try 8-7-7-21, 7-7-7-24, 8-7-8-21/24, you'll just have to experiment. Honestly you can probably run cas 6 or maybe lower if setup correctly. You set the voltage manually correct?

 

[killafaz]

That's right mate, I set the voltage to 1.65 manually and set the timings to 8-8-8-24 manually too. If I'm lowering the timings should I still keep the voltage set to 1.65 manually? Sounds good, thanks for taking your time to teach me these things! I definitely understand this a lot better now. Once I'm home I'll drop the timings to 7-7-7-21 and run memtest and prime95 blend the way you mentioned. I'll let you know how I get on.

One last question for the moment. In terms of performance gain by lowering the timings, is it something I would notice in the real world ie faster loading times for programs etc, or will it be something little like squeezing another couple of frames out of my games? It's something I want to do regardless to tune it all up as much as I can, but just wondering what to look out for in terms of performance increase.

Thanks once again, your help is really appreciated.

 

[sportsfanboy]

YW

No leave the voltage where it is, raising it can damage your processor. Honestly your ram as it sits is fast enough to make it difficult to notice a difference in real world applications, even after you lower the timings or raise the frequency. loading times is almost always bottle necked by the hard drive, and I doubt you will notice it in games either.

You'll notice a measurable difference in encoding/transcoding,large photoshop projects, and things like CAD work, and obviously synthetic benches.

 

[killafaz]

I just gave it a go, and I made a mistake in my first post. I actually had the timings on 9-9-9-24. I instantly changed them to 7-7-7-21 and as soon as the config was saved and the PC started to boot, I was told by the bios that 'Overclocking has failed'. I went back into setup and changed the timings to 8-8-8-24 and I'm just about to test that stability. Is there any reason why this would fail so qucikly? Any other settings I should change etc? I'll let yu know if 8-8-8-24 is stable.

Cheers.

 

[sportsfanboy]

You can also try giving the QPI/dram a small bump in voltage, that might help a little. Unfortunately you just need a whole lot of testing. Messing with memory timings is basically trial and error.

 

[killafaz]

Really appreciate it all man. I've just ran prime95 blend for 30 minutes with no errors. Going to run a memtest now (did it back to front cos needed to do something on my PC ASAP). Once that's done I'm just gunna play some games to see how it goes, and every couple of nights I'll play around with the timings. I'll have a lot more time on my hands over Christmas so I will get it completely tuned by then. Thanks for the advice, I've learned a lot.

Take care mate.

 

[sportsfanboy]

You too