GPU Memory Clock Freq ??

[J_D]

I've been overclocking my Graphics card over the last few days and have slowly now got to a point were I’ve got the core clock to a stable position

Stock 300Mhz
OC 410Mhz @ Max Temp 78C

I want to move on to overclock the memory. I’ve done some research and it looks like I wont be able to overclock the memory clock above the manufactures Max Freq. anyway I’ve found the print name and code for my graphics card GDDR SDRAM

SAMSUNG
K4D261638F TC40

(See Close up)
http://www.doomedpc.com/images/reviews/xpert6600/P1010039.JPG

And I have tracked down the Chips Data sheet.
(Scroll to page 3)
http://www.samsung.com/Products/Sem...128Mbit/K4D261638F/ds_k4d261638f_tc_rev15.pdf

It says K4D261638F TC40 MAX Freq = 250Mhz

Well now here is my problem

Everest says ~200Mhz

Rivatuner says ~400Mhz

And the Nvidia controls panel says 800Mhz!!!!

On experimentation if I increase the clock via coolbits in the NV Control panel (Shown above) by 20Mhz to 820Mhz then rivatuner goes up by 10 and Everest goes up by 5. So it is in proportion.

Can some one explain this to me?
Am I right in saying the 400Mhz is the effective clock freq due to DDR

From research the average GF 6600 AGP Mem Clock is 275 but can have a larger range so I assume that the Everest value is the one I want to watch. So it looks like a bought a pretty slow clocked 6600.

And would I be able to overclock above the manufactures req freq? of 250Mhz

Anyway i hope someone to could clear this up for me.

Cheers

 

[elitehacker]

Yeah Riva Tuner is show the effective Mhz frequency, the nvidia control panel is totally wrong though.

 

[J_D]

Ok, thats what i thought, I think i can pretty much ignore it as they all increase in proportion

So should i aim to only overclock the memory to 250Mhz (500Mhz effective). As this is what i found to be the MAX Freq for my GDDR SDRAM according to Samsung.

 

[Styrak]

400MHz DDR = 800MHz effective