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I have just built a new system and am wondering if it is operating as it supposed to be.
The major components used are as follows:
Mobo: Gigabyte GA-MA74GM-S2 Rev.1.0, BIOS v.F3
CPU: AMD ADO4800IAA5D0 -- Athlon 64 X2 4800+ Brisbane
RAM: 4GB(2GBx2) DDRII800 -- A pair kit

I thought the BIOS would take care of the initial setting but noticed that the core speed was set for 1000MHz. So I modified the multiplier from x5 to x12.5 and the core speed was changed to 2500MHz. That's all I could do. My question here is what CPU-Z shows for HT Link, DRAM Freq, and FSB:DRAM as follows:
HT Link: 1002.3MHz
DRAM Freq: 357.9MHz
FSB:DRAM: CPU/7

Are these normal? Why is DRAM Freq not 400MHz?



Edit Post

If amd cool 'n' quiet was enabled it was probably throttling the cpu. Best way around that is to test with something running 20%+ cpu usage, it should auto scale it to max speed. From my experience,. auto doesn't make mistakes with cpu speed, it can with ram, usually because it defaults to JEDEC rather than EPP profiles, or just fails to recognize it properly. That's not the issue here though.


The ram is running slower because of the divider, I'd imagine. When you switched to manual you must have left it at some non-optimal settings.

Yup RAM clock will end up below spec on AMD mobos depending on the RAM divider that lines up with the CPU multiplier. RAM clk = CPU clk / RAM divider.

Thanks everyone for your response.
The Cool'n' Quiet is disabled. The Bus speed shown on the CPU-Z is 200MHz. The multiplier is manually set for x12.5 thus the core frequency shown is 2500MHz.

Both of you indicates that the RAM frequency is lower than the normal or rated speed.
Then what is the normal speed?
How can the normal speed be realized?
Is the HT Link of 1000 normal?
What does FSB:DRAM of CPU/7 means?
How does the System Bus(MT/s) of 2000 which is in the spec of the CPU relates to the above?

Both of you indicates that the RAM frequency is lower than the normal or rated speed.
Then what is the normal speed?
How can the normal speed be realized?
Is the HT Link of 1000 normal?
What does FSB:DRAM of CPU/7 means?
How does the System Bus(MT/s) of 2000 which is in the spec of the CPU relates to the above?

The memory controller on K8s is on the CPU die, and memory frequency is derived from the CPU clock not the HT clock. The HT clock and CPU clock are both derived from a base clock supplied by the motherboard.

Only even CPU multipliers will allow DDR2 800 to run at 400MHz. Your CPU is 2500MHz which divided by 7 = 357MHz. Dividing 2500 by 6 would yield 417MHz. No whole divider will give you 400MHz. If you lower your CPU multiplier to 12x you would have 2400MHz CPU and 6 divider would give you 400MHz for the memory.

HT is a DDR bus, so a 1000MHz clock = 2000MHz data rate. The base clock of 200MHz supplied by the motherboard is actually clock multiplied to 1000MHz on the actual bus.

Personally I would overclock the CPU to 2800MHz and keep the 7 divider, and your memory will run at 400MHz then. You can overclock the CPU by raising the base clock to 224MHz which would result in a 1120MHz HT clock.

Bombadil wrote:

Both of you indicates that the RAM frequency is lower than the normal or rated speed.
Then what is the normal speed?
How can the normal speed be realized?
Is the HT Link of 1000 normal?
What does FSB:DRAM of CPU/7 means?
How does the System Bus(MT/s) of 2000 which is in the spec of the CPU relates to the above?

The memory controller on K8s is on the CPU die, and memory frequency is derived from the CPU clock not the HT clock. The HT clock and CPU clock are both derived from a base clock supplied by the motherboard.

Only even CPU multipliers will allow DDR2 800 to run at 400MHz. Your CPU is 2500MHz which divided by 7 = 357MHz. Dividing 2500 by 6 would yield 417MHz. No whole divider will give you 400MHz. If you lower your CPU multiplier to 12x you would have 2400MHz CPU and 6 divider would give you 400MHz for the memory.

HT is a DDR bus, so a 1000MHz clock = 2000MHz data rate. The base clock of 200MHz supplied by the motherboard is actually clock multiplied to 1000MHz on the actual bus.

Personally I would overclock the CPU to 2800MHz and keep the 7 divider, and your memory will run at 400MHz then. You can overclock the CPU by raising the base clock to 224MHz which would result in a 1120MHz HT clock.

Thank you very much for your detailed explanation.
I would like to ask a couple of follow-up questions:
1) Is it correct to say that there is no fractional divider such as 6.25 for deriving the DRAM frequency, and that this number is automatically set or not alterable by the user?
2) I have difficulty understanding "HT is a DDR bus, so a 1000MHz clock = 2000MHz data rate." How does the HT being stated as "DDR bus" relates to the DRAM frequency of 375 or 714MHz? Isn't this the DDR data rate?
3) If the CPU is overclocked to 2800MHz by raising the bus to 224MHz, do the PCI bus of 33MHz and PCIe bus of 100MHz stay the same and unaffected?

DDR means Double Data Rate. Don't confuse this with DDR SDRAM, Double Data Rate synchronous dynamic random access memory. That's the RAM in your system.
When he says Hypertransport is a DDR bus, it means that data is transfered at twice the rate of the bus's clock speed (the data's rate of transfer is doubled).

If you increase the speed of the Hypertransport link, it won't affect the PCI and PCIe clocks. (I think... anyone wanna back me up on this?)

You can manually adjust the divider. Look in your BIOS for it.

Yes PCIe and PCI clocks are separate from HT. Unless you go back to the olden days of VIA K8T800. That was before PCIe existed though heh.

grantmeaname wrote:

When he says Hypertransport is a DDR bus, it means that data is transfered at twice the rate of the bus's clock speed .

Thanks for your response.
OK, I got that. Now how does the Hypertransport data rate relate to the DRAM data rate? Are they independent of each other?

You stated as "If you increase the speed of the Hypertransport.....". Can the Hypertransport speed be changed by user?

I think that my question 1) is not answered yet by your response.