Matching CPU to RAM

TBSN

Senior member
Nov 12, 2006
925
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76
Hey guys,
I've got a couple (general) questions about OCing and RAM. I just wanted to see if I'm understanding the concepts correctly, I'm really learning about this for the first time.

Firstly, it generally takes better RAM (higher speeds) to get a CPU like the e6300 to overclock because the FSB needs to be higher with the limited multiplier on the CPU, right? So having an e6400 would allow you to run the Ram at slightly lower speeds...

example: e6300 @ 457fsb x7 = 3.199Ghz (ram must be 914mhz)
e6400 @ 400fsb x8 = 3.200Ghz (ram must be 800mhz)

OK, so if I haven't already screwed up, here is my next question:
If (in a theoretical situation) the the CPU is clocked at the same speed in two situations, but the RAM is at a higher clock speed (such as when using a lower multiplier+ higher FSB), is the memory faster, or does it just equate to the same thing, in terms of overall speed?

I know that these aren't exactly 'real-world' questions, I just like understanding the technology before I make decisions and buy it :). Any help would be appreciated!

-B
 

Conky

Lifer
May 9, 2001
10,709
0
0
In that theoretical situation the system with the RAM at a higher speed with the CPU speed being the same would be the faster system. It would also probably be more likely to be unstable unless the RAM was very expensive and overclockable.

I'm aiming to overclock an E6400 to 3.2Ghz with some DDR2-800(PC2-6400) RAM which will not even be overclocking the RAM. This should be a fairly easy goal to achieve.

One of the goals of overclocking, or at least it used to be, is to get the gains for free or for very cheap. Stability is also very important because an unstable overclock is worthless unless you don't mind the idea of your system rebooting during an online deathmatch or while you are burning a DVD.

Buying $500 RAM and overclocking an E6300 is sorta retarded when you can spend a little more and get the E6400, a reasonable heatsink fan, and be able to overclock nicely with some cheaper RAM.

That's my 2 cents on overclocking anyway. :)
 

TBSN

Senior member
Nov 12, 2006
925
0
76
I'm also planning on getting an e6400 and bumping it up to 3.2Ghz with DDR2-800 RAM. Is it possible to overclock RAM by keeping the speed the same, but simply lowering the timings? Does this require extra voltage?
 

n7

Elite Member
Jan 4, 2004
21,303
4
81
If an E6300 & E6400 are overclocked to the same speed (like in your scenario) with the memory at the same timings (generally this is unlikely btw), the E6300 would be faster, yes.

However, good RAM is indeed key with an E6300.

It's actually not hard to find RAM that can achieve 500 MHz (DDR2-1000) speeds, but when you start really pushing things, then motherboards tend to become an issue too with E6300s.

The only ones that will nearly always hit 500 FSB are the P5B Deluxe/P5B-E, & alot more voltage to the mobo is needed to maintain stabililty usually.

Usually the Gigabyte S3/DS3 also.

The nice thing about the E6400 is it's a bit more flexible as you can run it @ 8x multi or 7x, & combine that with 1:1 or 4:5 RAM, & i'd say you'll be able to get the absolute best of out your components more easily than with the E6300, since you are pretty much stuck to 7x 1:1.

Regardless of which route you go, there is great OCing D9 RAM for as little as $245 (Buffalo Firestix) & up.
 

Conky

Lifer
May 9, 2001
10,709
0
0
You can always try tighter memory timings and see if they work. Extra voltage might help although I suppose it depends, like so many other things with overclocking, on plain old luck.

And I'm not sure that tighter RAM timings are considered overclocking the RAM because it would still be running at the same speed.
 

TBSN

Senior member
Nov 12, 2006
925
0
76
cool, thanks for the help guys. Now I just have to decide whether I want to go with a 680i chipset or 965 like p5b-d...
 

n7

Elite Member
Jan 4, 2004
21,303
4
81
Seriously, considering the very high price, unless you need SLI, i wouldn't bother with 680i.

P965 is the best value around right now; allows for spending more money toward CPU/RAM/GPU, where you'll really see a difference :)
 

cmdrdredd

Lifer
Dec 12, 2001
27,052
357
126
I still want to see 680i memory bandwidth testing with 1t vs 2t vs p965 vs 975x at various common DDR2 speeds (removing the CPU from the equation). It's not hard to run at DDR2-800, DDR2-1000, DDR2-667 and then see what the max overclock on the memory is (use the same memory for each board).

Where is this test I need to see?
 

TBSN

Senior member
Nov 12, 2006
925
0
76
Hmmm, I think I will go with a P965, like you said. I'm trying to decide between the P5B-E or Deluxe... Anyway, I'll post that in the mobo section I guess. Thanks for the help!