Due to the size of the mod and all the added content, there is a dropoff in performance. In the mod's last thread I did a poll asking whether or not people would like to see more things (skins, units, abilities, etc...) at the cost of some perfromance. The answer was an overwhelming "yes". So, you may have to lower graphics settings from what you normally play CoH or other mods. A simple rule of thumb is making sure the "memory usage" bar on the graphics settings page does not go above 1/3. A basic "minimum requirement" for RAM memory appears to be about 3GB of RAM. You will need about 4GB of USABLE RAM (which would mean the need for a x64 bit OS) to play on high settings, and about 6GB of RAM to start playing bigger games on high or Ultra.
For those with less than 4 GB of RAM, a x32 bit operating system, or who are having graphical crash issues - keep ALL the settings other than 1) Shader Quality, 2) Model Quality, and 3) Texture Detail on low or off ALL the time. They're just about useless in the big picture (that comes from thousands of games watched and played, so I have to STRONGLY suggest doing that at least for the mod if you are having crash issues). Keep Shader Quality and Model Quality on "high" all the time. Also, keep the model detail slider bar in the middle (though that seems to make no difference). The only thing to adjust is the Texture Detail. "Medium" texture detail is pretty much the default setting for just under 4GB RAM, although you can try high and see if it works for you. If you're using Wehr on a 3v3 or higher and already having issues, I suggest low. If you are going to mix factions, I STRONGLY recommend low if you are already having issues- maybe medium for a 2v2 where it's PE vs. a US and Brit mix - but never high for a mixed faction game with less than 4-5 GB of USABLE RAM. Obviously if your having issues, dropping one of the 3 main things (texture detail first) may be necessary.
My old CPU specs : Intel Core 2 Quad Core Q8200 @ 2.33 GHz x32 bit Vista 4 GB Ram NVidea GeForce 250 GS 1024 MB. The above suggestions both worked and were needed with those specs
I then installed Windows 7 x64 bit (no other changes). Basically meaning I was able to use my full memory due to the x64 bit OS (x32 bit OS's are only able to use about 3.5 GB's of RAM minus your graphics card memory). I then was able to play mixed faction games on Ultra and High settings. So, the mod is VERY dependent on RAM memory, and for better performance you need more memory.
My newest rig has much higher specs and there are no issues at all (9GB RAM)
BASICALLY - LOOK AT THE ABOVE GUIDELINES, JUDGE YOUR COMPUTER SPECS AGAINST THEM, AND FIND THE "SWEET SPOT" WHERE YOUR RIG CAN PLAY THE MOD WITHOUT ISSUES