Am I going to see a noticeable difference in RAM speeds doing video applications, gaming, music production applications?

4GB 667MHZ vs. 4GB 800MHz?

Thanks

Am I going to see a noticeable difference in RAM speeds doing video applications, gaming, music production applications?

4GB 667MHZ vs. 4GB 800MHz?

Thanks

Is depend on your Mainboard, CPU and Graphic card if you see an noticeable difference.

If the memory you have is let say 1 x 1 GB 667 CL3 and you cange to 4 x 1GB 800 CL5 the speed may more slow. The CL is one important figure but you can egneral say, lower CL are the faster.

So if you want to change, take a close look at the CL value.

Cheers. 

Like Reimar said, the higher latency of the faster ram can cancel out any effect from running at a higher clockspeed. Here's a comparison of DDR2 533 (CL2) vs DDR2 667 (CL3): HERE

Ideally, you want to find memory that runs at the higher clockspeed but has a low latency.