Can you mix memory with different CAS timings?

[blues02]

Hi. I have an Athlon XP2200+ on a Soyo KT600 DRAGON Plus motherboard. It has 3 DIMM slots. I had 2 sticks of PC2100 DDR in the first two (1x128, 1x256), and a 512MB stick of PC3200 in the last one. The FSB is set to standard 266Mhz. I have been having issues in one application, system stuttering but not crashing. I did a system report that showed the PC2100 sticks had a CL2.5 timing, I don't have the rest of the number with me but I think it was 2.5-3-3-8, and the PC3200 has a 2.0-2-2-6. Is this a problem? Do all the sticks have to be the same timing? I have no problems in applications like Windows Movie Maker, Roxio, iTunes, Doom3, Pirates!, etc. But in this one program, City of Heroes, I have system stutters at random. I ran memtest86 for 12 hours with no reported errors but as soon as I took the PC2100 out all together and took the 512 stick and put in in slot0 the game ran error free. Is it bad memory or a timing conflict? Or should I put the memory back in and keep looking at other things? My system is up to date and spyware and virus free.

If this has been posted before I apologize, I did a quick search and didn't find anything.

Thank for any help.

 

[SilthDraeth]

I do not think your problem is associated with the RAM at all. City of Heroes is an MMORPG

Massive Multiplayer Online Role Playing Game.

In short, even though the majority of the game is loaded onto your computer, your computer still has to constantly update with what the server is sending it, and talk back and forth.

What is the speed of your internet connection? What is the draw distance on the game set at?

"I just noticed you said, while running one stick, the game runs error free"
I am sure that when you run 2 different speeds of memory, your overall memory only runs as fast as the slowest part.

It could be due to the constant need to update with the server, that your RAM is taking a bigger hit.

How does COH run, with jut the 2 sticks of 2100?
If it is still jittery, but isnt with a single stick of 3200, then I would say my guess is probably right.

With one stick of 3200 you're ram is running at 400 mhz, as opposed to 266mhz. thats almost 50% faster.

 

[blues02]

I'm running a DSL connection, and I'm right next to SBC's switch or whatever you call it so I get fast connections with no real variation in speeds. The drawing distance is set to the default of 100%.

When I'm running the PC3200 the bus speed is still be set by the CPU at 133Mhz(266 with the DDR function). The CPU is locked to 13.5x133Mhz bus. Everest Home Edition system profiler is still reporting it at 133Mhz Bus and CPU frequency of 1800mhz, which is normal. So the system is running the PC3200 RAM at PC2100 speed, otherwise the CPU would be clocked to 2700Mhz (13.5x200).

I used to run it with the same MB & CPU, but with 512MB of PC2100 RAM( and a Radeon 9000 Pro video card under Windows 2K. It ran slower, with the frame rate being a little choppy at times, but I never got this problem.

It's not "choppy", like when the FPS drops below 30 in this game or Doom3. The system is hanging for 5-10 seconds with the last sound being played stuttering over and over until the system goes again. This is a lot different than the lag I'm used to in online games. This is locking the application up, not rubberbanding me or anything like that.

Anyway I'm assuming that you are saying that you can run the different memory timings/latency without a problem? They will all just run at the slowest rate? I'm trying to eliminate the potential problems. And I don't know if that could cause a conflict

Any other ideas? I'm really looking for help here. I'm going to upgrade to the AMD XP3200+ CPU at 400Mhz bus in a month or so but I'd like to use all my current RAM until that time.

 

[SilthDraeth]

Hmm. I think running the memtest86 answers your own question.. though I am not sure why COH would hang...