I'm building a new gaming pc soon (X3 720 and a 4870) and was wondering if I should buy a new SATA drive with 16/32 mb of cache. Would there be a worthwhile preformance increase over my 8mb cache IDE drive ? Trying to save as much money as possible but I don't want my system limited by my HDD.
you WILL bottleneck with IDE. SATA is muck better. i don't think IDE has a capacity greater than 500GB max anyway. every aspect of IDE drives are becoming outdated because all the new models are made SATA compatable. IDE is dead.
There is no difference between SATA and IDE, except burst rate, which is directly related to the relatively small cache size, and some (becoming more everyday) SSD drives. It's not the the SATA bandwidth but the fact that your drive is old and slow.
Your 7200.7 has an average read of ~45MB/sec. the 640AAKS has an average read of ~90MB/sec. This is due primarily to PMR (Perpendicular Magnetic Recording).
So you will double your speed and that will most definitely be noticeable.
You would see no performance increase, except burst rate, if the 6400AAKS was a PATA drive, because it would not be outrunning the bandwidth PATA provides.