does low ram reduce k/hash ??

[novymivo]

hi all
I just added my fifth card to my mining rig on win 7.
-win 7, asrock 81btc, 5x r9 780x.
and after added fifth card k/hash dropped from 700 to 550 on the same or similar settings.
I got 4gb dual ddr3 1600.
-or maybe this is psu issue ( I got lepa 1600 w)
-or maybe because I changed the drivers to ccc 12.6 with sdk 2,7 and cgminer 3.7.0 to let my windows see 5 cards ? but now all of my card are marked as r7990
ANY IDEAS ??

[neter]

you changed many things at once. start from scratch. r9 series are polished 79xx series thus it's normal that win7 sees as 79xx card but also signals that you messed up smtg

if i were in your place i'd start with one card (the latest you plugged in) only to be sure that there's no psu issue (psu might be not enough for the card to produce target khash) and the OS sees the card as it should; then add one by one the others, watching for output after each.

[neter]

btw, 4 gb ram is enough for cgminer to run.