Windows 7.1 + Cubase 7 + Yamaha FW interface

Hello Windows + Cubase + Yamaha experts
To eliminate latency and never lose another Cubase project, I bought a cheap Dell Outlet T7500 Xeon 6-core processor with 32Gb RAM and 4*15000 RPM SCSI drives in RAID 5 mode. I have an MR816csx connected to the good Texas FW chipset.
Result: I have glitches all the time on replay and my latency is never better than ~20 MILLIseconds In or Out. If I try to get the latency lower, the glitches become impossible. I use DPC Latency Checker and its reads latency as 2-5 MICROseconds with massive glitches every 15-20 seconds. I have no problem recording apart from the latency.
All my OS, software, drivers and firmware are fully up to date. My Windows Performance monitor shows only one CPU is active at nearly 100% all the time with only Cubase running, so multi-CPU is obviously not happening. My Windows ‘experience’ scores only 6.6 out of 7.0 because of ‘reduced disk transfer speed’. If I disable my LAN connection, the glitches go away, but latency does not improve. I do use a lot of soft synths and FX in every project but hoped the CPU and RAM would make this OK.
Please can anyone help?

I don’t think RAID5 is the best setup for a realtime multi-streaming system. Might work if they were SSDs.

Perhaps just use one drive and do ad-hoc mirroring backups to another during breaks.

You are right; RAID 5 I/O is very lop-sided which I didn’t realise until after Dell configured it - my mistake entirely. Maybe I should re-install a separate ‘production’ drive for OS and Cubase and use the RAID for backup. What is the size and config of your SSDs, please and what latency are you achieving?

  1. OS (General boot) = 120GB OCZ Vertex 3 (but only 75GB for OS, 24GB free; the other 44GB is a spare partition)
  2. OS (DAW boot) = 120GB OCZ Vertex 4 (but only 62GB for OS, 25GB free; the other 49GB is a spare partition)
  3. Data (non-DAW) = 60GB OCZ Vertex 2
  4. Projects = 232GB Samsung 840 EVO, 123GB free
  5. EW Piano samples = Corsair 250GB full
  6. EW et al samples = Corsair 250GB full.

At 192k and 256 sample buffer while recording, 4ms round trip latency (1.3+ms recording, 2.7ms playback).

Also make sure your raid controller doesn’t have any know issues.
We did a raid setup once and found out the on board raid controller was the 1 most often reported as BAD for audio.

We dumped the raid and went with daily backups, offline, after hours.

Thanks all - this has been so helpful. My system came with a dedicated ‘PERC’ RAID controller card which is probably very good but I should have chosen RAID 0+1 or 10 for speed. But using 2x or 4x the disk space, I would have already exhausted it due to my extravagant ‘Lose Nothing’ policy. I have an idea to install a RAID 10 array of SSDs on my unused SATA motherboard connectors, re-install OS and all Steinberg apps and resources on that and only load ‘active’ projects to save disk space. Would this work or should I go for a PCIe-mounted SSD setup?