Building new pc, starting fresh, please advise

[Houdy]

Hello all, I am a new face around here, but a long-time lurker.
With the fact that my current system has been up and running for 2years, I haven't had any reasons to keep up on current hardware technology. That time has come and gone and now i'm giving my wife my comp and building a new one.
I would post this in another forum but considering i am going to cover a few ranges of hardware pieces, i couldn't decide where to put it.. if mods see fit to move this, i will understand.

i am posting here because i will oc my stuff.. that's a given. having said that.. i have narrowed down my choices to 2 possible setups and i would like some assistance in my decision. up for the task? read on!

current system:
amd xp 2800 oc to 3100'ish
geforce 6800 128 (unlocked to GT specs)
1 gig ram (no oc'ed)
ATA 150 hard drive
MSI nforce 3 Neo mobo
cd / dvd burner
350w antec case
-running XP pro.. NOT 64 bit

it should be noted that i am a gamer..
WoW/BF2/Fear/wolf:ET/Rise of Legends/etc.. every good FPS, RTS, MMO.. i will play them all. I do plan on playing all the next FPS's as well.. and i want them to look good.

it should be noted that i have been an AMD user since i stopped using my cely 300.. i know nothing of intel these days.

what I am looking at
System 1
-AMD Opteron 165
-Asus A8N5X mobo
-G. Skill, 2 gigs pc 3200 mem
-Radeon x1800xt 256meg vid card
-Aspire xInfinity 420w PSU+case
-cd/dvd burner
-250gig SATA western digital hd
stock hsf..could pick up aftermarket.. suggest?

newegg price: $1012.00
----------------------------
System 2
-Intel Pentium D 805 Smithfield
-ASUS P5LD2 Deluxe Socket T (LGA 775) Intel 945P
-G.SKILL 2GB (2 x 1GB) 240-Pin DDR2 SDRAM DDR2 533 (PC2 4200)
-ASPIRE X-Pider ATXA2XP-AL/500 500W Daul 12V (V2.03) Power Supply
burner/hd/vid the same.
Scythe SCNJ 1000p HSF ..heard i might want a new hsf vs stock and this has been mentioned

newegg price $945.00


---=---
now, a few questions:
would it be better for gaming performance to grab a 7900GT over the x1800xt?
the radeon is a tad cheaper.. and no matter where i go on the net, i can't find a damn comparision that has both of those cards in it. (all the reviews either pit the radeons vs other radeons or geforce vs geforce.. i cant find a good review putting those two cards against each other).
also.. do you think i'll see a big diference in the video speed over my 6800(gt) 128 meg?
would you suggest a different vid card alltogther? i do not plan on going SLI..dont want to afford it.

on to mobos..
did i pick the right ones when it comes to oc'ing? i don't need the most expensive.. but i want a mobo i know has been proven to overclock. very often on the forums i see people say "i got my opty/pentium to this speed.. " but then they dont list their mobo or say they dont like it. i have yet to see a review saying "heres the opty 165.. and here are the 5 boards we OC+tested it on"..
i just want to know if those boards are good for OC'ing.. if not.. please suggest others. I did notice people said to stay away from the Nforce boards for intel.. gotcha. but what else do i need to look for when it comes to the Pentium mobo?

<--PSU-->
how much power is really needed for what i am looking for on the Pentium? i read that they are beasts.. and something about dual rail.. did i pick a decent PSU for that?

last but not least..
when the AMD cpu is $327 and the pentium cpu is $128.. which chip am i going to see the best oc'ing from and the biggest performance difference vs my puny xp3100 taking into consideration price.

any all an constructive criticism appreciated.. i will answer any questions you throw back at me.
thanks a ton fellas.

 

[Crusty_Ass]

Hi there. Just a few quick pointers:

DDR-II 533 is slower than DDR-400. If you really need to go DDR-II try to buy some faster stuff. This is an argument against intel, as they favour DDR-II right now.

However, Pentium D 805 promises better performance than Opteron right now.
The 805 is probably the better overclocker.
You can buy an AMD X2 4000+ for the same price as the Opteron.

Scythe Ninja is the best cooler around btw, good choice.

Aside from that, Asus has been getting some flak lately for several of it's motherboards, EVEN though they usually get rave reviews. Check similar products from alternative manufacturers like Gigabyte, DFI and Msi.

On purchase, be sure to place a fan to cool your harddisks, they'll last longer.
Any airflow is better than no airflow at all.

 

[batboy]

I will challenge Crusty's statement that DDR2-533 is slower than DDR-400. Perhaps the DDR-400 will have lower latencies depending on which RAM you are talking about, but 533 is definitely faster with more bandwidth than 400.

Houdy, you'll need a better PSU on that Intel system. That Aspire just won't cut it. Need something like the OCZ 520W Powerstream.

 

[Brando]

You should probably get the ati card. 7900gt's are still prototypes with serious issues that need to be ironed out.

 

[Houdy]

i went ahead and made some changes..
and i posted in the intel-specific forum. If youc are to see what i am going to get.. head here:
http://www.ocforums.com/showthread.php?p=4504223#post4504223

thanks for the heads up fellas.. and for those not wnting to follow the link, i changed out the PSU/case as recommended.

 

[White_Pawn]

with x1xxx cards, you should get 512 mem. I hear it hurts to have those cards but less than 512.