Mac pro slows down after RAM uppgrade ASP (its my workstation)

Question

I have an mac pro (first 8core released back in 2007) and i uppgraded it from 4 to 8 gig of ram. After the upgrade it became slower so I installed snow leopard since it should handle ram and multicores better but that didnt help. Its like it go from sleepy to extreme slow. Like an photoshop image that should take 12 seconds to load took 10min!! So its somethin fishy.
The old configration
DIMM Riser A/DIMM 1: 1 GB
DIMM Riser A/DIMM 2: 1 GB
DIMM Riser B/DIMM 1: 1 GB
DIMM Riser B/DIMM 2: 1 GB
DIMM Riser A/DIMM 3: 0 GB
DIMM Riser A/DIMM 4: 0 GB
DIMM Riser B/DIMM 3: 0 GB
DIMM Riser B/DIMM 4: 0 GB
The new uppgraded
DIMM Riser A/DIMM 1: 1 GB
DIMM Riser A/DIMM 2: 1 GB
DIMM Riser B/DIMM 1: 1 GB
DIMM Riser B/DIMM 2: 1 GB
DIMM Riser A/DIMM 3: 2 GB
DIMM Riser A/DIMM 4: 2 GB
DIMM Riser B/DIMM 3: 0 GB
DIMM Riser B/DIMM 4: 0 GB
Does 2007 have 4 memory chips as ideal as 2006 had? Can the macstore give me bad compatible rams (i asked for orginal mac ram memmorys). If this could make it go slow. Mabe snow leapord helped out to slow it down but I worked one and half day before I uppgraded to snow leopard and it was already slow.
This is on my worskstation so its Asp. Is there any heros here?
(ok I will test to take out the ram and se if everything goes back to normal but still I would like to get it to work)
Cheers
Joel

Answer 1

"need" is something that is "recommended" for symmetrical memory performance.
It shouldn't run any different really.
I always recommend this:
try with just the new RAM
put highest density in A1:A2
It is symmetrical, sort of, as 4x1GB in slots 1:2 on both Risers.
My take: doesn't play nice or get along with original 4GB; marginal; and ideal is 4 x 2GB; second best 8 x 1GB. 6 DIMMs is the worst configuration AFTER not having enough.
I'd wipe out your swap files; clone your drive - if you haven't done so in six months you should, also if moving to a new OS, DEFINITELY either
Clean install on new/2nd drive (great excuse for new fast drive);
Clone and then upgrade (worst scenerio)
Clean install followed by running Migration Assistant for everything except applications.
Don't want to have issues with new OS, new drivers, AND new hardware (even RAM) and a new OS isn't going to fix a problem, just add new ones. And TEST a new OS before you commit yourself (reason for backups and clones and the like).
Also, run Disk Warrior on fresh clone before you use it.
What you do, why, you probably did need more RAM, 4GB is pretty basic and not even enough for pro apps like graphic editing.
Watch RAM temps and run AHT Extended Loop briefly.
I'd watch for bad blocks and disk sectors; re-initialize drives, even install some new ones: WD 10K V-Raptor for system and another for scratch; Samsung 1TB F3 for data.... something like that if it has been 2+ yrs.