Is the OLD memtest good enough

I see memtest+ has support for newer things (prescott etc). But is the old memtest still gonna pick up errors on my system (in sig)

As long as the revision you're using was released after your board's production date, you should be fine. However, I'd consider upgrading because

1) It's free.
2) The newer program may include compatibility upgrades
3) It's free.

~THT