ASUS P5Q3 Deluxe discussion

[Amurtigress]

Hi people,

I have finally gotten my system stable, and after some thorough research I am coming to the conclusion that the board is perfectly fine, except for a stupid BIOS bug.

We all know it, when you're setting the memory timings manually for the first time, the AUTO entries are being changed to display the default memory timings. What's extremely irking and a spoiler to me, too, is that the defaults of the P5Q3 Deluxe board are 5-5-5-15. This is ridiculous tho, as we all know, the crucial timings are roughly doubling for DDR3 RAM. So we are setting our timings to something like 9-9-9-24. All fine and well, the problem in my opinion is the ACK# to ACK# Delay (tRRD) setting. It is not stored in the SPD, hence there's only ASUS faulty default of 5 clocks. And this is exactly what did not allow me to get prime stable, and potentially was driving lots of others up the wall.

Setting ACK to ACK delayed to AUTO will always put it at 5 (DDR2 typical!), while 8-10 is required for DDR3. You can find that, for example, in the forums of the OCZ support or at Corsair. So I think I have a good professional backing up for my thesis.

Another step to getting our board stable is tRFC. 60 is often not enough either. Corsair for example programs their SPDs to 41 in the XMP profile, which is usually ignored by the BIOS. Dual Channel requires twice the SPD's programmed value, so I recommend 82 or more for stability.

You can roughly determine your instability cause by the kind of issue you have. Too tight tRFC usually leads to sudden bluescreens and system resets, while the too tight tRRD is giving you errors in Prime 95, Orthos 2004 or OCCT.

Another factor is the Common Performance Level. The BIOS has a tendency to recommend lower values than 9, but at least 9 should be set manually. I am using 11 myself right now.

I hope this helps. Here's a lil screenshot of my memory settings....if you need to see more, let me know.