Ket
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Sapphire Radeon HD 3870, looking for some memory timings? - 2008/06/25 20:50
Hi folks, some of you may recognise the username so to save the private messages, yes its me, ket. Anyway now to the point in hand! I got me a Sapphire Radeon HD 3870 with 512MB of GDDR3 memory, and its a nice card, but it suffers from one gigantic flaw, there is something not quite right with its BIOS and the 1.0ns Qimonda memory which my card has won't even quite reach its rated speed of 2.0GHz as it maxes at 1.96GHz. I stopped by the Sapphire forums giving lots of details and findings, but in a nutshell found the replies to be very rude, and obnoxious. Should of come here in the first place.
Anyways given I haven't done much in the way of looking at Radeon HD 3xx0 series BIOS files, does anyone know how to change the memory timings in these BIOS's yet? Here is a copy and paste of my inital post in the Sapphire forums, has all the info you guys should need. I'm reviewing the Radeon HD 3870 with 512MB of GDDR3 memory for a number of websites as well as something else to add to my portfolio. The issue I have encountered is the memory on this card won't reach 2.0GHz effective.
I have checked the rating of the memory IC's and they are 1.0ns Qimonda, so they should deffinately be able to reach 2.0GHz. I've also felt the memory IC's idle and load, load they are rather toasty, so I don't think the IC's are running a lower than white paper specs voltage. The BIOS revision on this card is 010.080.000.001 and driver version being used is Catalyst 8.6. So, my final conclusion I'm lead to is that there is some timing adjustment that needs to be made for these memory IC's to run stable at their rated manufacturer speced frequency.
Does anyone have any other suggestions or can verify my suspicions about some memory timings needing to be adjusted? Of course if somebody could post an updated BIOS for the card fixing this issue that would be awsome and improve the final verdict score in the review. I'll upload a copy of the BIOS which I've already modified apart from the memory timings issue for some folk to look at.
It looks like the CAS latency just needs changing from 11 which is for the 1800MHz or 1.1ns rated memory to 12 which should be the CAS latency spec'd by Qimonda for 2000MHz operation an sorry for this massive post, but it saves the info being fragmented in several posts. 
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ASUS 8800GT PCIe 512MB - Rev 04
even better if you can find why the memory wont at least clock to 1000MHz*2 like its rated for.
