Memory,how fast is fast

[WHYWONTIT]

Sorry to be slow and misinformed but what speed memory (fsb and cas) do you need to achieve an overclock like on the 90nm 3000 64+ review (290x9). I am in the process of buying a new rig and wanted to know if you need pc4000 or higher or is pc3200 enough. Also it looks like a waste of money buying a 3500+ if a 3000+ can achieve the same clock,or am I missing something..???

 

[AristoV300]

Go with OCZ Platinum PC-3200. It runs at DDR400 speeds at the tightest timing and can run above DDR500 speeds at CAS 2.5. Gives you the biggest flexibility.

 

[Gamingphreek]

No go with the Crucial Ballistix. The best memory out there right now.

-Kevin

 

[WHYWONTIT]

I have 2 sticks of low latency cas 2 Corsair pc 3200( 2x256),anyone know if these are upto the job(290x9)???

 

[cbehnken]

just set a divider on your mem and run your mem at about 240

 

[BW86]

i agree with getting the crucial ballistic series, supposedly the best ram for the a64. Or you can get some pc3200 value ram and set a divider like i did

 

[Concillian]

The Samsung TCCD chips are just as good as Ballistix it seems, and seem to reliably run 260+ MHz. Gskill, OCZ platinum Rev. 2, PQI turbo, whatever. All the recent reviews (on more than just AT) have been able to get 275, and people at forums like pcper.com and xtremesystems.org.

People are seeing things like this with the TCCD chips:
http://xtremesystems.org/forum...php?attachmentid=17288
That's one DIMM only, apparently 2 DIMMs reduces capability some on S754 boards. Also, this guy seems to have gotten an extremely good sample.

 

[prometheusxls]

Originally posted by: BW86
i agree with getting the crucial ballistic series, supposedly the best ram for the a64. Or you can get some pc3200 value ram and set a divider like i did

Word
I am not sure RAM speed makes a big difference in gaming. I am not sure extrea ram over 512MB makes a big difference. I wouldnt be surprised if the difference in gaming performance between 512MB of ram at 400MHz add 1GB ram at 500MHz was more than 7%. So I doubt its worth the extra $200 it should cost.

 

[Doctor W]

I guess I missed the boat with the first AMD64 overclocking articles. The memory can be set to a ratio of the HTT, correct? So if we are doing 290 HTT (as so many of us will be, I imagine), there would be some way to use my existing PC3500 (I believe it does 217 at stock voltage at pretty sharp timings, can probably go a little higher w/ 2.8v and relaxed timings).

I was somewhat concerned after reading the NF4 article, because if you look at the nTune screenshots, there is a single slider for HTT/memory, but I imagine the memory clock will just inrease/decrease along with the HTT at the same ratio? So... is there a 3/4 ratio or so for the AMD64's memory controller? That would be 217 exactly.

 

[Concillian]

There is a 3:4 ratio only on the DFI LANparty UT board (at least currently)

Typical ratios are 5:6, 2:3, and 1:2

However it is important to keep in mind that the A64 will only run memory at a speed that is an INTEGER divided by the CPU speed. This is so the memory clock is always "in-sync" with the memory controller clock (which runs at the speed of the CPU).

So with the 9x multiplier and 290 HTT:
5:6 is 241.667 BUT 2610 / 11 = 237.27, so your RAM will actually be running at 237 MHz
2:3 will yield an actual of 186 MHz
1:2 will yield an actual of 145 MHz

The 9x multiplier is kind of a pain in terms of RAM without motherboards offering a list of integer dividers. The first motherboard that just gives integer dividers will probably be hailed as revolutionary.

By integer dividers I mean allowing CPU / 10, CPU / 11, CPU / 12, CPU / 13, etc...
I mean why even deal with the ratio BS when the memory won't even run at those actual speeds?

The other thing that you need to be careful with is running X.5 multipliers. 8.5x290 at 1:1 will not run 1:1, since 290 will not be an even integer divided by the CPU speed. The actual memory speed will be 274 MHz

 

[Zebo]

Originally posted by: Concillian
The Samsung TCCD chips are just as good as Ballistix it seems, and seem to reliably run 260+ MHz. Gskill, OCZ platinum Rev. 2, PQI turbo, whatever. All the recent reviews (on more than just AT) have been able to get 275, and people at forums like pcper.com and xtremesystems.org.

People are seeing things like this with the TCCD chips:
http://xtremesystems.org/forum...php?attachmentid=17288
That's one DIMM only, apparently 2 DIMMs reduces capability some on S754 boards. Also, this guy seems to have gotten an extremely good sample.

I'm gonna have to disagree here. TCCD will clock a bit higher but Ballistix will maintain 2-2-2 all the way up into the 245 range per tests done at vaious review sites.