paul2955tw :
Hi, I'm wondering if 550watts psu will be enough to crossfire 7870 or not.
How much watts will you recommend if it isn't? Thanks in advance
Hi - realhardtech recommends 600w to CF a system
with 2 7870's. That means you could "get by"
with a quality 550w unit as they and the PSU
calculators build in xtra to allow for among other
things PSU that don't deliver their published
specs and there are a lot of em out there.
Also, if you don't want to be using molex
to PCI-E adapters, you need to look for a
quality PSU that has 4 PCI-E adapters as
7870's require 2 each. Generally, you start
to see PSU's with 4 PCI-E connectors at
650w & above.
Also, a note regarding another post. Very often
there is an efficiency benefit to using a higher
power PSU than you need, and that is that
very often (while gaming) you will be in the
PSU's "sweet spot" efficiency range, which
is usually 40-60% of it's max output. I.E.
if you are using 325w during a CF gaming session
that would be 50% of a 650w unit's max, and
most likely it's most efficient range.
Tom