Need a photoshop rig for the shop. Quad or dual core?

[Big Gulp]

Okay, I've been using my media computer as a half-assed Photoshop computer here at the tattoo shop for a while now.  I do a lot of drawing with a pen tablet, and since I bought this computer just to run Windows Media Center and play .avi files it's just not up to the rigors I put it through, particularly with a resource hog like iTunes running in the background.

I'm ready for a new computer, but my love of shiny, powerful technology is conflicting with my inherent cheapness.  Keep in mind that I work in really high resolutions (like drawings at 300 dpi, 6000 pixels wide), and while a dual core works fairly well I still get little problems every now and then like lag when I switch from one tool or another to the brush.  Basically I'm looking for arguments that'll counteract my cheapness and force me to get a quad core with 8 gigs of RAM (which in a sick way will make this computer better than my home rig).

[Mrbloodworth]

Photoshop is CPU and ram bound. I don't even think the new 3D tools use the GPU. Filters take a good chunk of CPU to use, depending on what you are doing, and if you are a heavy layers user, and a fan of non-destructive editing, more ram is better. At the resolutions you are working at, Ram is your friend.

I recently put together a quad core, with 4 gigs for under $900, this includes the monitor.

[schild]

There's no reason for you to get a quad core with 8 GB of RAM. That said, you can probably get that pretty cheaply anyway.

You can get a quad core for ~200 (dual core will run $90-$150 for the faster ones) and 8GB DDR2 800 for like $100.

So, yea, cheap.

[Lantyssa]

The price difference is small enough it's worth going for a Quad.

[Jobu]

You could downgrade to an older version of Photoshop if you want to be cheap. Assuming you are using CS3 or something right now, CS1 or PS7 will work fine for line drawings and inking. Save your money for a Cintiq. 

[Trippy]

Photoshop makes very good use of multiple cores. A quad core will be significantly faster than a dual core if you do a lot of filter work. It's also one of the few major programs at the moment that runs noticeably faster on the new i7 processors.

http://www.tomshardware.com/charts/2009-desktop-cpu-charts/Adobe-Photoshop-CS-4,1387.html
http://www.anandtech.com/cpuchipsets/intel/showdoc.aspx?i=3505&p=2

[Big Gulp]

You could downgrade to an older version of Photoshop if you want to be cheap. Assuming you are using CS3 or something right now, CS1 or PS7 will work fine for line drawings and inking. Save your money for a Cintiq. 

Yeah, I'd love a Cintiq, but I balk at the 12" just because it's not big enough, and the 21" is a wallet destroyer.  I'm okay with my Intuos 4 medium at the moment.  Right now I'm running CS3, but I'll probably put CS4 on the quad core (yeah, I pulled the trigger and bought it) since it's got that nifty rotation hotkey, and I think I can simulate my compulsive paper turning with it.