scrypt ram

[how-high]

hi
I understood for scrypt ram was not important

but reading

Note that it is a ram dependent
workload, and requires you to have enough system ram as well as fast enough
GPU ram. If you have less system ram than your GPU has, it may not be possible
to mine at any reasonable rate.

when I go over intensity 12 I start seeing hw errors

I have 2gb ram and have this card

MSI R7950 Twin Frozr 3GD5/OC BE G Radeon HD 7950 3GB 384-bit GDDR5 PCI Express

does that mean I need more ram?

also when using 3 of these cards howmuch ram I will need?
and would a 800w powersupply be enough?

[how-high]

ok I think I get it
since the card has got 3gb of ram, I will need atleast 3gb of ram

so 3 cards will need  3 x 3gb = minimum 9gb of ram?

[how-high]

I see others using multiple cards with 4gb ram?

so what is it now?
is ram needed for scrypt mining? or not?

[toocool]

It is,

with more RAM, you can set higher TC, which on the other hand reduces HW errors.
4GB seems minimum for most 3-4 GPU rigs.
Mined with 2GB, got many HWs, after upgrading HWs' gone, WU's up.

FOr you 4GB seems fine, 800W as well (but good 800W, not cheap one).