you can't look at cache alone and compare drives, that's like comparing computers by screen size. newegg is down at the moment so i can't see what models you are looking at but generally if you stay with the same model drives the larger ones are quicker
According to those links the F3 1TB has a 32MB cache and the 500GB has a 16MB cache, but it doesnt matter too much, if you look at the hard drive charts you will see they are both close in sequential performance and pretty close to the top of the list, i would go for the 1TB for the extra space and their slightly better performance, plus its only $10 more for twice as much space.
99% of what your hard drive does in an average user's system is sequential reads or writes, rarely will you do something that is primarily random IO, when you are booting an application, its sequential, when you are saving a file, its sequential, when you are hosting a database that gets queried, its random.
I'll quote so you don't have to read those huge articles. I'm not suggesting an SDD, I'm just pointing out you won't see a benefit from raid.
The problem is that modern day OSes tend to read and write data very randomly, albeit in specific areas of the disk. And the data being accessed is rarely large, it’s usually very small on the order of a few KB in size.
This test writes 4KB in a completely random pattern over an 8GB space of the drive to simulate the sort of random writes that you'd see on an OS drive.
As we established in previous articles, the disk operations that feel the slowest are the random small file reads and writes.
What do you have in your system already? If your looking to increase your gaming performance AID0 won't do anything other then load the map faster. I would gladly wait an extra 5-10 seconds if that means I can turn on more details for the next 2 hours.
If you need speed for booting, program loading, etc. you will enjoy more by having an SSD. A single Crucial C300 is even faster than 2 WD Raptors in RAID 0.
Gaming doesn't need a fast HDD or SSD to improve the performance, you won't gain any extra fps by using faster HDDs, the games and maps load faster, that is all.
SSD is fast but expensive, again you willprobably need only about 50-128GB of space to hold your prgrams and operating system. The rest of the files go to normal HDDs.
The only reason you have to RAID your HDDs is if you need a large and not so fast configuration, let say for data servers.
RAIDing your HDDs for faster booting, loading, etc. belongs to yesterday since the SSD is available.