Memory Overclocking

[Blac]

I'm very good with processor overclocking...my AMD T-Bred B has been very good to me. I hear people talk about overclocking PC2100 memory to PC2700 and such...what exactly are they referring too?

Are we talking bumping the front side bus up encompasing this, or something else?

[EvilRick]

Upping the FSB is the only way. There are no multipliers or anything like that for RAM. Aggresive memory timings as well, BUT, when you get upto higher FSB's, you usually have to use less aggresive timings or it won't handle it. I don't remember if it was here or another site that had arguments about wether to have high FSB and lousy memory timings or vice versa, at some point, you aren't gaining anything.

In short though, upping the FSB will increase the PC2100 to PC2700 as far as MHz's is concerned.

[jmichna]

To supplement EvilRick's comment, you can increase the vdimm to help the ram handle the higher speeds and improve stability. I run all my ram (Corsair, Geil are the two brands I use) at anywhere from +0.20 to +0.30 volts over default. A few brands of ram need the over-volting to achieve stability at aggressive timings even at default FSB. Some brands of ram will tolerate even a bit higher voltage.
jmichna

[Blac]

Thanks, guys. Just making sure its the same thing.

[ArcticFox]

Uh......you can OC the RAM seperate from the FSB if you'd like. My A7N8X-DX allows this, so does every other "enthusiast" motherboard I've seen. This way, you can run the connection from your RAM faster than your FSB.

It's like overclocking a CPU - the internals of the proc may be faster, but the FSB still grinds everything down to 400 or 800Mhz or whatever you run at.

[beppodmime]

Keep in mind, however, that running the memory and CPU host clock (fsb) out of sync in an Athlon XP based system will actually DEGRADE overall system performance. Running the memory clock and the CPU clock at a 1:1 ratio is recommended for optimal performance. Just stick the memory clock at whatever max speed the CPU and the chipset can also handle.

[Darthgary]

My friend has a BArton 2500+ running at 2800+ with the memory locked at PC 2700 and the timings are not as good as they could be, I tell him all the time to do something about it but he acts like he does not even care. It ticks me off, I know he is not a newb but he can act like one sometimes.

[ArcticFox]

I thought that the 1:1 ratio thing for Athlon systems was only the "recommended" setup, but not necessarily the fastest. Am I wrong? Does anyone have benchmarks?

[jmichna]

Originally posted by ArcticFox
I thought that the 1:1 ratio thing for Athlon systems was only the "recommended" setup, but not necessarily the fastest. Am I wrong? Does anyone have benchmarks?

AF...
I have seen benchmarks from some time ago (maybe a year or so, when KT33 asynchronous was first released... and there is a real, measurable hit when running in asynchronous mode. It's been so long... if I can remember/find some benchmarks I'll post back. It had to do with the lag (hold) time required to coordinate between the 5:4 ratio versus "straight through" on the 1:1 ratio between buses.

I do run my KT333 systems 'synchronous' because the overall performance is "better."

[ArcticFox]

Well I'll take your word for it, it's a good thing I found out now before I purchased DDR466, that I will only need DDR400 as it doesn't look like I'll be overclocking the RAM in my nForce2 box.