RAM Ratio, RAM Overclock

[lenkeith]

Hi guys,

Pardon me if I may be repeating such a topic. I have been surfing around forums and tutorials but I don't seem to hit the sweet spot.

## RAM to CPU Ratio Question ##

RAM : CPU ratio, 1:1 is more desirable than 2:1? Is that right or wrong?

If your RAM is higher in ratio, does it mean the performance decrease but you get a more stable overclock because the RAM will have more bandwidth?
I understand if I get a 667Mhz RAM (333.5 actual), to get the ratio equal, you can OC for example an E4300 to say 3Ghz (9 * 333fsb).
If a 1:1 ratio is more desirable, would I loose out getting a 800Mhz RAM resulting in a 2:1?
(Besides the fact that I can further OC the E4300 in future to more than 3Ghz.)

## RAM Overclock Question##

I understand the timings like 4-4-4-12. But what is the math that calculates the RAM to 667Mhz? So if I wanted to overclock the RAM, what in BIOs do I change? The RAM timings and the voltage?

I read about suggestions to drop the speed of the RAM to get a 1:1 ratio with the CPU. But that would be loosing out on the RAM overhead isn't it?

 

[myocardia]

Originally posted by: lenkeith
## RAM Overclock Question##

I understand the timings like 4-4-4-12. But what is the math that calculates the RAM to 667Mhz? So if I wanted to overclock the RAM, what in BIOs do I change? The RAM timings and the voltage?

To calculate your RAM's speed, assuming you have it set in the BIOS @ 200 Mhz/400 DDR with an E4300, it will be running at exactly the same speed as the FSB. At stock CPU speed, it will be running @ 200 Mhz/400 DDR.

I read about suggestions to drop the speed of the RAM to get a 1:1 ratio with the CPU. But that would be loosing out on the RAM overhead isn't it?

Sure, you'd be losing bandwidth, if you aren't overclocking your CPU. But, good luck getting your 400 Mhz/800 DDR PC6400 value RAM running @ 667 Mhz/1333 DDR. If you're running your FSB (and CPU) @ 333 FSB, with your RAM multiplier @ 1:2, then for every Mhz that you raise your FSB, the RAM will go 2 Mhz higher.

 

[lenkeith]

Hey, thanks for your reply.

So what you are trying to say is that a 1:1 ratio is best? So it would make better sense to plan on what FSB I would want to overclock so that I can get a RAM speed that would match the FSB or if not, overclocked a little to match the FSB?
Rather than getting a RAM that would give too much bandwidth.

I guess I don't quite understand the pros and cons of having a 1:1 ratio or 1:2 ratio.

 

[myocardia]

First of all, there's no such thing as too much bandwidth. That would be like having too much money. But, you have to buy RAM that has a higher stock (non overclocked) speed than your processor has, or you'll never be able to overclock. Well, overclock very much, anyway.

If you have PC6400 RAM, and run your processor @ 9x333, then if you buy the right motherboard, you can use a multiplier that will allow your RAM to run @ or close to 400 Mhz/800 DDR. But, even if your motherboard can't do that, you'll get way more performance with your processor @ 9x333, and your RAM @ 333/667 DDR, than you would if your processor is @ 9x200, and your RAM is @ 400 Mhz/800 DDR. See?:laugh:

 

[lenkeith]

AH!!! Yes yes I totally understand that now. Coolness! Ok anyway, I will understand more once I get my hands on experience in overclocking. Gonna get E4300 and probably 400mhz/800 RAM then start overclocking.

Ok one more question. Say for some reason I don't manage to push the FSB to meet the RAM frequency getting a ratio of 1:1. Instead I get a higher RAM ratio of CPU:RAM 1:2.
Would that be not so good? Seems to me like getting a 1:1 ratio is ideal for most people.

I read a sticky in extreme overclocking forum stating this:

"Running RAM faster than the CPU offers mildly better performance than 1:1. If you have found your CPU's max, and have the headroom to run a divider that will run the RAM faster than the CPU, then go for it. Limiting your CPU overclock to run the RAM faster than the CPU, however, will reduce performance. Again, go for the highest CPU FSB possible first and foremost."

When he states 'the headroom to run a divider that will run the RAM faster...' He means a higher RAM ratio correct?