OSNews

But SSD raids do not pass trim command and performance degrades over time, or did they fixed that?

I learnt the hard way. The RAID 0 failed.

I got RAID 1 so I can swap another drive in there if one of the SSD fail.

It isn't perfect.

I dunno if Windows 7+ sorts that or not. I am not that bothered. For 2 years I had more than 300mb/s transfer rate. The performance was worth it.

Edited 2013-02-21 20:11 UTC

Processing power of the GPU is always a problem if you want to implement nice visual effects. More graphic calls/second, the better.

it is, but it is a solved problem for Hi-def screens.

Ram and latency are most definitely an issue. Just as Disk I/O is orders of magnitude slower than RAM access, RAM access is orders of magnitude slower than Cache access.

No matter how fast your storage (disk) subsystem can spit out data, it's not going to be anywhere close to as fast as getting it from memory. And ditto, getting data or instructions from cache is far superior to making the processor use it's memory controller to look up an address from some page table and do the virtual to physical lookup.

If you have enough RAM to fit all the game data into sytem RAM, so much the better. Unfortunately, SRAM is way too expensive, and even now, 128K Harvard architecture split data/instruction caches is considered pretty good. Getting access to L1 cache can take just a few clock cycles. Getting memory from system RAM takes a few hundred clock cycles generally speaking. But whereas system RAM access is measured in micro or even nano seconds, disk IO is stilled measured in milliseconds. In other words, disk access is thousands of times slower than RAM access. If you're page faulting and have to swap to disk, you're in BIG trouble in a game. The idea is you pull data from storage into RAM. RAM times are so important, that many developers don't even use malloc or new, and they pre-allocate their own heaps (memory allocation is expensive and can put the processor to sleep, not to mention the problem with memory fragmentation).

In regards to processing power, the name of the game is concurrency. Many systems are now merging the concept of CPU and GPUs so that the massively parallel processing of GPU's can work on all the highly vectorized game data (usually graphics, but physics too). But many other components will still rely on the main CPU (artificial intelligence for example). Splitting data across multiple threads of execution is very challenging.

Is a game more GPU or CPU bound? Depends on the game I suppose (I'm not a game developer, I'm a storage controller device driver developer). But again, processing and especially optimizing parallelization and concurrency will provide FAR greater beneft than disk IO.