CPU and FSB

[idahoduk]

I ordered the wrong MB for my Dad. I ordered a 748 and he has a socket A. The board has two sockets 748 & 939. He has a Semptron 2400 and 1G of Micron PC2700. I'm going to order a 939 pin AMD 3000. I'm almost positive I need DDR400 since the FSB is 1600 (or 2000???) can I use the Micron DDR333? Has anyone overclocked thier RAM that much before.

 

[Wouter]

hello,

off course you can use the DDR 333. your motherboard supports DDR400 and lower. what do you mean by overclocking your RAM??? overclocking the speed or the memory???

wouter

 

[MrBucket]

i think this just raised more questions than answers, moderator come quick!

 

[Ku-sama]

yes, you can use PC2700 in a PC3200 motherbaord, i suggest getting new RAM thats ment for DDR400 speeds rather then overclocking it

 

[diduknowthat]

well first of all, it's not called FSB, its HT, but that's just a minor error . Anyways, i would suggest that you get new ram, but if you decide to stick with your pc2700, you'll need to overclock the ram by 44mhz to obtain pc3200 speed.

 

[Geoff]

As others have said, it's perfectly fine to use DDR333 memory in that motherboard, it will just run at a slower DDR333 speed.

 

[idahoduk]

Sorry for the mistake. HT. Hyper Transport. I know I can use DDR33 on that board but what if the Processor requires DDR400, that was my question. If I run the HT at 333 then the processor will basically be underclocked correct?

So you can run DDR333 at 400HT. We'll see if we have a stability issue. Thanks for the help and sorry for the confusion.

 

[Cromewell]

That's why A64s have memory dividers

 

[idahoduk]

And memory dividers are?

 

[Arm_Pit3]

I dont know hwo to eexplain it well, but your RAM should work fine still.

 

[Cromewell]

Memory Divider This is one of the most Confusing aspects of A64 Overclocking. There is ALWAYS a memory divider. Setting the Memory to 1:1 means that the HTT bus is multiplied by the CPU Multiplier and then Divided by the CPU Multiplier to set the Memory speed. This means that it is OK to run your Memory at its peak efficiency and still go higher with your HTT bus if your CPU can take it. Take note that I said its "OK" not advisable. There are still sufficient tests out there showing that running a 1:1 ratio will garner you the best overall performance. I plan on adding a few test results in the next week or so showing the difference in performance using a higher memory divider than CPU Multiplier.

Since A64's use an On chip memory controller, the Ratio must be calculated a bit differently than old. 5:6 is NOT always 5:6. See that chart at the end of this post for a prety darn close representation of what each divieder is doing.

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