just a quick question

I have been overclocking processors for years, normally I would have a fixed multi and have to up the RAM frequency to get the best OC for that processor.

Nowadays, it seems you have the likes of 48x100 type stuff. I have seen examples of this everywhere but cant understand why RAM is not overclocked like it used to be...

I'm soon to upgrade and would like some understanding on the reasons why the above example is so prevalent, especially when there are so many examples of high speed RAM available.

Thanks
rangi

On older systems (Core2, etc), overclocking was mainly done through the FSB because of the lower multipliers and expensive "extreme" versions. Since the FSB was directly tied to the RAM speed, running the processor faster (with FSB overclocking) would run the memory faster.

Today, the BCLK is generally locked on boards, and overclocking is done almost exclusively through the processor multiplier. Think of overclocking today's systems like you would overclock an unlocked Core2. You can still run the memory faster, but there isn't much of an improvement past ~1600 MHz if I remember correctly.

http://www.anandtech.com/show/4503/sandy-bridge-memory-scaling-choosing-the-best-ddr3/8
QUOTE:when you get down to DDR3-1333 that you see a minor performance penalty. The sweet spot appears to be at DDR3-1600, where you will see a minor performance increase over DDR3-1333 with only a slight increase in cost. The performance increase gained by going up to DDR3-1866 or DDR3-2133 isn't nearly as pronounced.

+2 to that Thid 100% correct on the OC, maybe we could give rangi a Little New Years present a 10 year badge in his avatar!!!! AJ.

Thanks for the reply, that was very helpful.

Why is the BCLK locked on most boards? If I wish to up the speed on my memory why not have the opportunity to do so, just seems that is a backward step.

Ajay, good catch. Rangi, I've given you your 10 year badge.

rangi said:

Thanks for the reply, that was very helpful.

Why is the BCLK locked on most boards? If I wish to up the speed on my memory why not have the opportunity to do so, just seems that is a backward step.

Click to expand...

To say it is locked isn't exactly true, per se. The BCLK is locked to the PCIe frequency, which is 100 MHz. PCIe does not like to be overclocked and very bad things can happen if you push more than 104-106 MHz on a day-to-day computer. For example, most hard drive controllers also go based off the PCIe clock and you can get some severe data corruption if you run it too fast. So it isn't that you can't, it is that you don't want to because overclocking via the multiplier is much easier and much less prone to error.

Just like the processor, there is a memory multiplier (different boards call it different things). So, you can still overclock your memory. You just don't do it through the FSB anymore, you do it through RAM dividers.

Well from what i gather from the Net Intel changed the design so they can put a igpu in with each chip hence lowering the overall cost. Which meant it was no longer viable to put out low cost chips. So that happened with the Sandy Bridge CPU's onward that has the igpu integrated in them. AJ.



Congrats for 10 years on OCF Rangi!

LOL ten years...I've been overclocking a long time, it a hobby, a addiction, a technical challenge. Just to get that little more FPS, oh the shame lol

Ok looks like the new stuff needs alittle more research, thanks y'all for your help. 1600MHZ sweet spot huh? So there goes my idea for 2400MHZ modules! yet i will investigate further, as it seems illogical for there to be no noticeable performance gain with higher speed memory...At least it gives me something to investigate further.

Thanks

Just as a foot note i have seen that Ram modules over 1600 mhz can cause instability problems in the new CPU platforms. And also the amount of ram as well bearing in mind the new motherboards can have 32GB. And in some 64GB which is a lot compared to the old days. And yes i really like this hobby and getting slowly hooked myself lol. AJ.