PC games run slow on my 6gig RAM Asus CM series PC Windows 7, why??

A little more info on your cpu and graphics card setup would be useful. Unfortunately, the size of your RAM only tells us the size of your RAM, it doesn't give us an indication of the performance of your machine.

The ASUS website quotes the CPU as Core2Duo/Core2Quad which can range from something pretty poor to something reasonable by todays standards, and the graphics as anything from Intel onboard to an ATi 3450/NVidia 8400 which probably don't even meet the minimum requirements for the game. It may be in it's original configuration or you may have upgraded since. Either way, it's useful to know what's in the machine.

Thanx for thr response. The computer is in its original configuration, I havent added anything to it. All I see on the box is ASUS CM1630-08 and then some other numbers. I dont know about CPUs and dont know about the graphics card. I thought it needed a new NVIDIA driver but when I went to download the driver update told me I didnt have NVIDIA on my computer.

I'll upgrade but I dont know exactly what I need.

You need a dedicated graphics card which may also require a new power supply. Read this to help you select a graphics card http://www.tomshardware.co.uk/gaming-graphics-card-revi... I suggest you don't go above the buget section as your CPU is dated.

Will check it out thank you.

Alittle more info on my computer;
The CM1630-08 comes with a 2.8GHz AMD Phenom II X4-830 processor and 6GB of RAM. On our CPU-intensive PCMark Vantage (5,723) and Cinebench R11.5 (3.35)

http://www.pcmag.com/article2/0,2817,2383156,00.asp

Because it only has a 330w PSU, the best video card I can recommend is the Radeon HD 7750. Click following link for benchmarks. Note that the test rig has an Intel i7-920 @ 3.8GHz.

http://www.techpowerup.com/reviews/ASUS/HD_7750/6.html

most of the cm series are media pc's ie for browsing the web and video and emails. not gaming. they do have a video card but more often than not its not a gaming card.
if you have a decent card ie a 4850 or 5670 or better then it maybe you have dx11 enabled without applying the fix the game crawls at 10-15 fps if your lucky. 1s you apply the fix the game will run properly ...

the fix
Go into C:\Users\...\Documents\WB Games\\Batman Arkham City\BmGame\config then delete bmengine, bmgame and userengin. Start the game with launcher and reconfigure your settings

1s done the game will run smoothly even with dx11 enabled.

Really?

I will try that.

Next option was buying the NVidia 550 and a new power supply. That should do it.

Thanx everyone for the input!