Hello.
Thanks for reply. I did not find legacy drivers but i solve my problem by flashing bios to the newest version and let BIOS choose the freq of RAM(even if they're running now 1066 even they are 1600) . Finally latency spikes are gone and DAW is working great.

I did try everything. Win7, WinXP, different version of cubase, different version of drivers for RME fireface 400, like twenty others things I found on the internet. Flashing Bios was my last chance before me going totally to nuts.

Anyway I post configuration of my system as it is now stable and maybe someone can find it usefull.

SUEZ DAW specification

Power Supply Nexus RX6300
http://www.nexustek.nl/Nexus_RX-6300_Mo … y_630W.htm

Motherboard gigabyte GA-EX58-UD5
http://www.gigabyte.cz/products/mb/spec … d5_10.html

Processor Intel® Core™ i7-930 (2.8 GHz)
http://ark.intel.com/Product.aspx?id=41 … ode=I7-930

Processor Coolin Hyper 212 Plus with 1xNF-S12B ULN
http://www.coolermaster.com/product.php?product_id=6603
http://www.noctua.at/main.php?show=prod … amp;lng=en

Memory 2xKingston HyperX Genesis 2GB 1600MHz
http://www.kingston.com/hyperx/products/khx_ddr3.asp

Graphic Card gigabyte GV-N98TSL-1GI (9800GT)
http://www.gigabyte.cz/products/vga/spe … l-1gi.html

Case Fan 1xNF-S12B ULN
http://www.noctua.at/main.php?show=prod … amp;lng=en

HDD WD Caviar Black WD2001FAEX 3.5" 2TB
http://www.wdc.com/en/products/products.aspx?id=100

Sound Card Rme Fireface 400
http://www.rme-audio.de/en_products_fireface_400.php

Cubase 5, Windows XP SP3

And RME fireface 400 flashed to version 1.71 but I'm using old version of drivers 2.5.8.0 as newest worked well when I was using Cubase, but when i switched it off they went to nuts. But if I again swirthed on cubase they goes back to normal. Don't have that problem with 2.5.8.0 drivers.