Asus P5Q-E true hardware RAID?
The box my motherboard came in said hardware RAID, someone swore up and down it really was hardware raid, so I called Asus who swears it's hardware RAID, but I'm still not convinced, is it really hardware RAID? Or is it just the same old host RAID every motherboard manufacturer says is hardware RAID?
It depends on the RAID type and CPU. RAID0 or RAID1 on a fast Core 2 or Quad has little impact. RAID5 requires more power, but again the impact is only a few percent. If you have an old P4 CPU, then the impact will obviously be more noticeable. Unless you're building a high-end server or workstation with several disks, spending $600. on a hardware RAID controller is difficult to justify. A low-end hardware RAID controller might be slower than the on-board RAID.
Actually, the P5Q uses a JMICRON hardware raid chip in addition to the Intel raid that the ICH10R chip provides. If you look on your motherboard you will see two SATA ports that are different colors. Just refer to your motherboard user manual.
I cannot be 100% sure, but someone mentioned you may get better performance from the ICH10R ports. This may or may not be true, because I don't know how fast the JMICRON processor is, and it has been proven that bandwidth is strictly limited by the processing power of the RAID chipset processor, and since the ICH10R is "soft raid" and relies on your CPU, the amount of bandwidth is essentially "unlimited". The difference may also be so slim that it does not even matter.
I think the primary purpose for the JMICRON chip is the ASUS software "Drive Xpert", which provides a GUI tool to easily backup your data... Not to mention it will avoid any strains on your CPU like GhislainG said.
All build in Mother Board RAID engines are NOT hardware RAID.
It is Fake RAID - Linux term. Other calls hardware assist RAID
You may think with all CPU's Cores that we have it's should not be a problem to utilize host CPU, right? Depend.
There are couple issue involve:
1 - RAID engine coding - how effient were coded wiht firmware and drivers. This is why some RAID card runs better than other
2 - RAID level: RAID1/0/10 ARE OK to use with MB's RAID, where RAID5 there may be a potential problem, due to more calculation for parity
3 - Number of drives: Although the SATA has been improve a lot, still it requires IRQ (interrupt requested) assist to run by issuing IRQ This process may not take much of CPU power, but definitely cost the system time.
When use 5 or more drives and RAID5 this in turns generate both hardware IRQ and software IRQ this can be problematic for the host system.
So the HW raid - although IO processor does not pose much of power but elimiate lot IRQ from the HOST's CPU, there for system is faster and more efficient.
That is why all the high end system IT guy always use HW raid
Here is the ref: http://en.wikipedia.org/wiki/Interrupt#Performance_issues