Overclocking Q6600 advice

[imported_trefork]

I haven't assembled a PC in nearly 6 years, and I'm finally getting ready to build a new one.
I'm planning on getting a Gigabyte P35-DS3R MB with a Q6600. I've never overclocked before and wasn't really planning on it for this one, but the Gigabyte MB does not support 533 memory, only 1066/800/667. 1066 seems a little too expensive, and I've read that using non-integer multiplier speeds is actually slower, so 667 or 800 would be slower than 533, which is half of 1066, the FSB speed. So, this leads me to this thought:
Can I set the FSB to 1333, effectively overclocking the Q6600 to 3Ghz, and then use 667 memory? Any thoughts on that configuration, and are the any voltage issues I need to be aware of in general and specifically for the memory?

Thanks.

 

[SerpentRoyal]

Quality DDR2 667 like the 1GB HP RAM ($22AR @ hot deals forum) should be able to run at 400MHz with 2.0Vdimm/5-5-5-15-2T timing. Stock speed is 333MHz. Too achieve 3.0GHz core speed, you'll need to push the memory speed to 375MHz. This would be the cheapest way for you to break 3.0GHz.

 

[MarcVenice]

Using a non-integer multiplier isn't a problem, as long as the ram runs at half or more the fsb of the cpu. I say half, because it's double pumped as you probably know. So for a fsb of 266, which is 1066 qaudpumped, you need ram like ddr2 533 anything faster like ddr2 667 or 800mhz is fine. For a FSB of 333 which is 1333 qaudpumped, you need at least ddr2 667 or better.

And even when using a non-integer multiplier where the ram doesn't run at half the cpu's fsb, it's usually okay too. Used to be for amd 64 cpu's at least. CPU speeds trumps memory speed. But since memory is cheap, there is no need to not run your memory at at least half the cpu's fsb.

@serpentroyal.

Why does he need to push the memory speed to 375 to reach 3ghz? 9x333 = 3.0ghz, and thus only needs ddr 667mhz to run 1:1 with the memory.

 

[imported_trefork]

Quality DDR2 667 like the 1GB HP RAM ($22AR @ hot deals forum) should be able to run at 400MHz with 2.0Vdimm/5-5-5-15-2T timing. Stock speed is 333MHz. Too achieve 3.0GHz core speed, you'll need to push the memory speed to 375MHz. This would be the cheapest way for you to break 3.0GHz.

Could you elaborate on that? I thought the memory ran better at a multiple of the FSB, e.g. for 1066 FSB, 533 is recommended, so I figured when bumping FSB to 1333, the natural memory speed would be 667. Where do you get the 375 from?

 

[imported_trefork]

Originally posted by: MarcVenice
Using a non-integer multiplier isn't a problem, as long as the ram runs at half or more the fsb of the cpu. I say half, because it's double pumped as you probably know. So for a fsb of 266, which is 1066 qaudpumped, you need ram like ddr2 533 anything faster like ddr2 667 or 800mhz is fine. For a FSB of 333 which is 1333 qaudpumped, you need at least ddr2 667 or better.

And even when using a non-integer multiplier where the ram doesn't run at half the cpu's fsb, it's usually okay too. Used to be for amd 64 cpu's at least. CPU speeds trumps memory speed. But since memory is cheap, there is no need to not run your memory at at least half the cpu's fsb.

@serpentroyal.

Why does he need to push the memory speed to 375 to reach 3ghz? 9x333 = 3.0ghz, and thus only needs ddr 667mhz to run 1:1 with the memory.

I recall reading somewhere that for the Core 2 architecture, memory performance is better when running synchronously with the FSB, which would make 667 slower than 553 for a 1066 FSB.

 

[SerpentRoyal]

Originally posted by: MarcVenice
Using a non-integer multiplier isn't a problem, as long as the ram runs at half or more the fsb of the cpu. I say half, because it's double pumped as you probably know. So for a fsb of 266, which is 1066 qaudpumped, you need ram like ddr2 533 anything faster like ddr2 667 or 800mhz is fine. For a FSB of 333 which is 1333 qaudpumped, you need at least ddr2 667 or better.

And even when using a non-integer multiplier where the ram doesn't run at half the cpu's fsb, it's usually okay too. Used to be for amd 64 cpu's at least. CPU speeds trumps memory speed. But since memory is cheap, there is no need to not run your memory at at least half the cpu's fsb.

@serpentroyal.

Why does he need to push the memory speed to 375 to reach 3ghz? 9x333 = 3.0ghz, and thus only needs ddr 667mhz to run 1:1 with the memory.

My bad...quad is 9x multi.

 

[SerpentRoyal]

Originally posted by: trefork

Quality DDR2 667 like the 1GB HP RAM ($22AR @ hot deals forum) should be able to run at 400MHz with 2.0Vdimm/5-5-5-15-2T timing. Stock speed is 333MHz. Too achieve 3.0GHz core speed, you'll need to push the memory speed to 375MHz. This would be the cheapest way for you to break 3.0GHz.

Could you elaborate on that? I thought the memory ran better at a multiple of the FSB, e.g. for 1066 FSB, 533 is recommended, so I figured when bumping FSB to 1333, the natural memory speed would be 667. Where do you get the 375 from?

Stock speed is 333MHz. I forgot that quad has 9x multi. On the plus side, you should be able to overclock the memory using 1:1.25 divider. Core speed is KING. However, fast memory will also boost performance by a small amount.

 

[fpbear]

I have a similar setup, with Q6600 G0, 4G Patriot DDR2 800 5-5-5-12, Abit IP35 Pro, Thermalright 120 Extreme, Antec 900 case. I am also a newbie first time overclocker and would be happy at 3Ghz. Can this be done with 800 RAM or did I pick the wrong parts? What would be the basic newbie-proof settings so I don't send the chip up in flames?

 

[MarcVenice]

800 ram is fine, ddr667 is fine too for 3.0ghz on a q6600. Just up your FSB to 333 in your bios, set pci express clock to 100, and pci clock synchronization mode to 33.33. They prolly are allready on those settings but should check anyways. That's it.

Then you gotta test for stability and watch temps. Use orthos to test stability, use coretemp, speedfan or cpu rightmark to monitor temps. Don't let em go over 60c. If you start at temps like 25c on your cores, then there's a bug, which means you have to add 15c to your temperatures. With stock cooling and ambient temps of 20-25c it's more reasonable to see your cores at 40c or so. I suggest reading an overclocking guide though, just to at least have the faintest idea what you are doing.

And trefork, where did you read this? I call bullshit, 200% bullshit. There's no real performance improvement exept for syntetic benchmarks running your ram at a higher speed then the cpu, but there sure as hell isn't a decrease in performance. The memory is simply providing bandwith, more bandwith is good, but past what the cpu can use, there's no need for extra bandwith so it simply doesn't get used. That's easypeasy explanation btw.

@ serpent, the FSB on a qaud is 266!!! 9x266 = 2.4ghz. Simple math.

 

[imported_trefork]

And trefork, where did you read this?

http://www.madshrimps.be/?acti...tpage=1965&articID=472

So it doesn?t matter much what memory speed/timings you buy, the value line will suit the Intel Core 2 system just fine, but do keep one thing in mind, as in our testing we found performance actually decreases a bit going from PC4200 (533) to PC5300 (667)!

The Core 2 has a front side bus (FSB) speed of 266Mhz x 4 (Quadruple) ?1066Mhz?, the ram is running at 266Mhz x2 (Dual Channel) x2 (DDR) = ?1066Mhz?, so with PC4200 memory and FSB are running synchronized. When you use PC5300 you are no longer running synchronous with the FSB and a memory divider of x1.25 (5/4) has to be used. The older Athlon XP from AMD also displayed this decrease in performance when running memory asynchronous due to its short pipeline, where memory latency is more important then memory bandwidth. With the Pentium 4 the pipeline was longer and the effect of running asynchronous which increased latency was masked. Core 2 technology marked Intel's return to a shorter pipeline and thus is more similar to the Athlon XP than the Pentium 4.

By running the memory synchronous to the FSB you have the least amount of latency and thus performance is at its best. Why is PC6400, which is also running asynchronous, faster then? Because the memory speed is now that much higher that it compensates for the loss of running asynchronous and overall performance does increase. PC5300 worked great with Pentium 4 but it should be avoided when running Core 2, except when you plan to overclock. PC5300/6400 will give you the extra headroom to increase the FSB while keeping memory synchronous.

 

[kokal]

Overall system performance does increase with increased memory speed - I have seen that in Anands's review about Core 2 Duos but can't remember which one - mostly games benefit from high speeds but there were some applications as well . If what you say about sync is right it has to be taken in thought that cheap DDR2 667 Modules run at 5-5-5-18(20) while cheap DDR2 800 modules run at 5-5-5-15(18-20) so 2nd second choice is faster (even if you decrease its speed to 667 you can run at 4-4-4-12). I would go with 2x1GB DDR2 800 Value Ram - my favourite has been PQI recently because it overclocks to 900-940 5-5-5-18@2.0V. Also I would go with the P35-DS3P because of better chipset cooling which can be kept passive - the picture in Gigabyte's site is out of date. The ones sold are with a bigger cooler which looks like a mini heatpipe tower cooler. Also it has firewire and is not much more expensive than your choice. Get a Q6600 G0 stepping and appropriate air cooling and run it at 3.6 with sync ram if you want to DDR2 800.

 

[MarcVenice]

DDR2 667 with 5-5-5-18 timings? Never seen those, maybe when they just came out ... 90% of the time the timings on lower clocked memory modules are in fact LOWER and thus BETTER then higher clocked ram. Thats why ram running at 667mhz with 3-5-5-8 timings or so will give better performance then ram running at 800mhz with 4-4-4-12 or even 5-5-5-15. It's not that big of a performance boost/loss though.

 

[imported_trefork]

Originally posted by: trefork
I haven't assembled a PC in nearly 6 years, and I'm finally getting ready to build a new one.
I'm planning on getting a Gigabyte P35-DS3R MB with a Q6600. I've never overclocked before and wasn't really planning on it for this one, but the Gigabyte MB does not support 533 memory, only 1066/800/667. 1066 seems a little too expensive, and I've read that using non-integer multiplier speeds is actually slower, so 667 or 800 would be slower than 533, which is half of 1066, the FSB speed. So, this leads me to this thought:
Can I set the FSB to 1333, effectively overclocking the Q6600 to 3Ghz, and then use 667 memory? Any thoughts on that configuration, and are the any voltage issues I need to be aware of in general and specifically for the memory?

Thanks.

So it appears I can easily do this. My only question then would be regarding memory voltage. What do I need to know. Should I get 1.8v or 2.2v memory, something else, or does it even matter?

 

[imported_trefork]

Originally posted by: trefork
So it appears I can easily do this. My only question then would be regarding memory voltage. What do I need to know. Should I get 1.8v or 2.2v memory, something else, or does it even matter?

In fact, I'm not even sure what the voltage rating means on memory. I'm looking at some 3-3-3-12 Crucial Ballistix 667 DDR2, which is rated at 2.2v. Does that mean it requires 2.2v or that its max voltage is 2.2? I may be an ignorant question, but I thought the the DDR2 spec required all DDR2 memory to operate at 1.8v.

 

[Midnight Rambler]

It means that 2.2v is required to run at those timings. Put another way, Crucial will only guarantee those timings at the specified voltage. Many times you can run at less voltage and reach the rated speed and timings, or conversely, run more aggressive timings and/or speeds at the spec'd voltage, but if you were to call Crucial TS to complain that your RAM won't run at the advertised timings (a hypothetical example), the first thing they are going to ask is are you running 2.2v. Bottom-line, this all depends on the quality of the IC's used for the RAM, as well as the module's quality and assembly. High quality modules like Crucial Ballistix, for example, will often come rated at moderately aggressive speeds and timings, but with a fairly stout voltage requirement, ie. 2.2v. Translation : The RAM can handle the voltage, no problem, and you probably have plenty of headroom for tweaking the RAM.

 

[imported_trefork]

Originally posted by: Midnight Rambler
It means that 2.2v is required to run at those timings. Put another way, Crucial will only guarantee those timings at the specified voltage. Many times you can run at less voltage and reach the rated speed and timings, or conversely, run more aggressive timings and/or speeds at the spec'd voltage, but if you were to call Crucial TS to complain that your RAM won't run at the advertised timings (a hypothetical example), the first thing they are going to ask is are you running 2.2v. Bottom-line, this all depends on the quality of the IC's used for the RAM, as well as the module's quality and assembly. High quality modules like Crucial Ballistix, for example, will often come rated at moderately aggressive speeds and timings, but with a fairly stout voltage requirement, ie. 2.2v. Translation : The RAM can handle the voltage, no problem, and you probably have plenty of headroom for tweaking the RAM.

Will increasing the voltage to 2.2 affect anything else, like the CPU or FSB, or something else? Basically, is there any side effects or gotchas?

 

[SerpentRoyal]

More voltage = More heat. More heat = Shorter life. Very good 1.8V DDR2 800 should be able to hit 450-550MHz with 2.1V and 5-5-5-15 timing. That's why you'll see Crucial Ballistix 1066 rated at 2.1-2.2V. Only a very small population will be able to run 1066 @ 1.8V.

There is very little gain in performance with C2D chips above 450MHz RAM speed. Higher speed will require slower timing.