Dumb Question???

[kuddin22]

Building a new system. Bit of a novice. Decided on P5Q-E and Q6600. Dilemma with memory:

Choice of 4G crucial ballistix tracer PC2-6400 C4 £80ish
4G OCZ Platinum PC2-8500 C5 £68

Which would be better?? Why??? Might be overclocking/changing CPU in future. DSF on another thread advised that DDR2 800 would provide ample headroom for the Q6600 but since then the OCZ price has fallen. Would I be silly not getting that seeing its PC2-8500 and cheaper. Or am I missing something?? I've heard a lot of good things about the ballistix and read something about D9 chips...

Please please advise. Thanks!

 

[Keitero]

I prefer Crucial myself since I've own a few sets of OCZ and a few Crucial sticks and found that I've had more problems with the OCZ. They tend to not work well at stock settings and requires a lot of tinkering to get it to play nice. On the other hand, the Crucial is more pricey. As for the D9GMK/X, those chips have a density of 1GB/module from what I hear. There is a variant of the 2GB that are rated for EPP and will do 4-4-4-12/15 without any issues.

 

[DSF]

Here's why I said DDR2-800 has ample headroom:

In terms of CPU speed and RAM speed, everything is based around your Front Side Bus (FSB) clock. The only thing is, Intel doesn't report the actual clock speed of the FSB, they report the number of transfers per second the CPU makes over that bus. This number is four times larger because the CPU makes four transfers per clock cycle. So for a processor like the Q6600 that's rated for a 1066 FSB, the actual FSB clock is only 266MHz. Each RAM module is capable of making two transfers per second - that's where DDR comes from, Double Data Rate. For this reason, RAM speeds are reported as twice the fastest FSB they're guaranteed to keep up with. DDR2-800 is guaranteed to work with a FSB of up to 400MHz.

Now let's turn our attention to CPU speed. Every processor has a multiplier that, in conjunction with the FSB, determine its overall speed. Deriving the speed of the CPU is easy, it's just FSB x CPU multiplier. So on the Q6600 you have 266MHz x 9 = 2.4GHz at stock settings. If you raise the FSB to 400 when you overclock, you get 400Mhz x 9 = 3.6GHz, which is about the limit of that particular chip, especially on air cooling. That's why I say DDR2-800 is sufficient for overclocking a Q6600 as far as it will go.

I'm assuming you're in the UK, and looking at scan.co.uk and overclockers.co.uk, I see a number of 2x2GB DDR2-800 modules for less then 80 pounds. Out of all of them, this Corsair DDR2-800 would probably be my choice. It's relatively inexpensive, is rated to run at 1.8V, and should do you just fine on a Q6600. Definitely wouldn't pay extra for the Ballistix Tracer.

However, you mentioned that you may change CPUs later on. With that in mind, DDR2-1066 may not be a bad choice. The extra headroom will help you if you change to a CPU with a lower multiplier, or one that can exceed that 3.6GHz ceiling that's about tops for Conroe and Allendale cores. Just be aware the you may need to spend some extra time fiddling with the voltages, and you aren't likely to see any real speed increase aside from the extra overclocking room.

 

[kuddin22]

Thanks for the input guys, appreciate it.

DSF, you mention about the corsair module being relatively inexpensive and rated to run at 1.8V. Whats the significance of the 1.8V as opposed to modules rated 2.0/2.2 etc? Does the higher voltage mean that theres more room to overclock?

I understand the basic maths in the first two paragraphs of your previous reply. Having not overclocked before, I dont yet understand what the relative advantages/disadvantages are between modules rated at 1.8V, 2.0V etc.

Maybe you or someone else could spare the time to explain or/and post some useful links that you have come across which would further advance my learning.

Once again, I appreciate your input and others in this forum. At the risk of sounding sickly, you guys make this forum great!

P.S since you're familiar with Overclockers UK, maybe you or anyone else for that matter, could recommedn 4gigs of 1066 memory. I get sidetracked with all the fancy heatspreads, lights etc!:thumbsup:

 

[DSF]

It all comes down to the official standard for DDR2 set by JEDEC. According to the official specification, DDR2 is supposed to be run at 1.8V, and that's the voltage motherboards are expecting to supply. All DDR2 modules are supposed to have at least one set of speed and timings which they can run at 1.8V so that in theory they can be used in any motherboard. It doesn't always work out that way though, and RAM that requires 2.0-2.2 can often cause system instability unless the voltage is manually adjusted in the BIOS.

If you're comfortable adjusting the voltage in the BIOS then higher voltage RAM doesn't really hurt anything, although you'll occasionally run into problems booting up the first time before you go into the BIOS to tweak the settings. If that happens, you need to pop in a stick of RAM that will work, change the settings, shut down, and put in your high-voltage RAM. Some people say running RAM at higher voltages generates more heat, and while I'm sure that's true, I don't think it's an issue in most cases.