Graphics 7800gt => x1800xl, worth it?

as title really. i am on a 19inch tft with 1280x1024. and i fancy the IQ and using hdr and AA at the same time with games.
what do you guys reckon between these 2?
ive already got the 7800gt btw but the x1800xl wont cost me much to get

and also, do the xl's need a really powerful psu to run them? ive got a antec neopower 2.0 and its only rated at 18amps on the 12v rail, but does it have 2 of these so it really has 18x2? ive not had much experience with these dual rail things

 

I've been out of things for awhile, but I can't imagine you'd get much of a performance increase by switching to the x1800xl.

 

im not really after a performance boost, just after better IQ and the same performance. i dont want to lose any put it that way

 

Well ATi are known for the better IQ and it does show in games. I'd reccomend the Xl. also 18amps isn't that powerfull but if it can run a 7800 Gt I see no reason why it can't run a Xl.

 

it is dual rail psu though whatever that means :s

 

Hehe, if you get a 1800, would you be intrested in selling your 7800GT at a reasonable price?

 

I would say, Definatly get the x1800xl. I did the same thing and noticed some big improvments to be honest.

 

As for the Dual rail PSU, it should be fine but if you plan to go Crossfire it is reccomended you use a single rail PSU (with higher amps), I have a Tagan EasyCon 580, i has a little slider at the back that lets you choose wether you want Dual rail or single. Though I'm not sure wether all PSU's use this...

 

7800GT 110nm 400/1000 20pipes 7vertex 256bitDDR Core=8000+6400+700 RAM=32.0
X1800XL 90nm 500/1000 16pipes 8vertex 256bitDDR Core=8000+8000+1000 RAM=32.0

That is paper specification and there's obviously architectural differences but it is good for a close idea of the performance differential, remember nVidia low ROP-to-pipe hurts them on paper but not in real world usage. So essentially performance would be very similar, it would mostly be OpenGL and Linux where there's likely to be any remotely significant difference as nVidia are easily stronger in these areas. ATi have long been famed for their very good '2D' IQ, ie. the image sent out to a monitor. For CRTs I don't think there's been much difference since the GF4 days myself and I believe there should be even less variance with DVI, nVidia cleaned up their act after the GF5/FX series which reportedly often had sub-standard DVI. In terms of IQ relating to in-game effects, AA & AF I'd say it's pretty even even though I haven't seen a good comparison with GF6/7 and X1000 cards. You would lose 'Digital Vibrance' control which can really make Windows seem much richer, try it on Medium, Low then OFF for a few hours each, I wouldn't like to lose that myself as simple as it is.

If your PSU is a dual-rail (ie. ATX12V2.0) then it should quote 12V twice, once for each rail. 18A on the 12V of an Antec branded PSU should be more than fine but if not it's only a drop in the ocean compared to buying pretty top-end cards like these. For an idea of power consumption (the cards are very similar) check out these ...

http://www.xbitlabs.com/articles/video/display/gpu-consumption2006_5.html

http://techreport.com/reviews/2006q1/geforce-7600-7900/index.x?pg=13 (ignore idle power readings)

 

cheers guys.
@fr4nk, im not going xfire as i have a nvidia board atm. and one card is enough, i only game at 1280x1024.
@austin, ihave no idea what the digital vibrance thing is, i dont think ill miss it to be honest. i do miss my old x800xt IQ though

 

and austin how do you work out the fill rate thing?

 

To check out Digital Vibrance select 'Display Properties' -> Settings -> Advanced -> 'nVidia card's name' -> 'Color Correction' and apply the setting to the Desktop. It's only when I switch back to an ATi card that I realise the difference this actually makes, the desktop seems so washed out without it.

Anyway to keep it simple fill rate is calculated by core clock speed multiplied by pixel pipelines, that's the 'Pixel Processing Speed' (Mpixels/s); 7800GT is 400x20=8000Mp/s. The 'Pixel Output Speed' is often the same but for 7800GT which has 16 ROPs to the 20 pixel pipes it's different; 400x16=6400Mp/s. Having fewer ROPs doesn't seem to hurt real-world performance even on the 6600GT which only has 4 ROPs to 8 pixel pipes, so the 'Pixel Processing Speed' is the more indicative figure. Of course paper fill rate figures don't factor in the many variables of modern gfx cards but it's still useful for a general idea and pretty accurate whent he architecture is the same such as 7800GT vs 7800GTX or 6600GT vs 6800Ultra.

 

cheers austin for trying to break me in slow. still not got a clue what youre on about though lol.
im basically wondering if an overclocked x1800xl would offer more performance over a 7800gt as thats what im led to believe and i know the x1800's clock like a midget on crack. would a xl at 600/600 be better than a GT?

 

You can get an idea of where a core is likely to clock to by looking at the higher family member which uses the same core. The 7800GT uses 400mhz with 20pipes while the 7800GTX uses 430mhz with 24pipes and the 7800GTX512 (with a double cooler and power) uses 550mhz with 24pipes (and probably plenty of extra voltage). I would imagine 7800GT could get 480-500mhz or so (a 20-25% increase). nVidia elected to use 110nm with 20-24pipes and lower clocks whereas ATi X1800 use the newer 90nm process with 16pipes but higher clocks, the smaller process generally allows faster speeds with lower voltage, lower heat and less power.

More importantly to you the X1800XL uses a 500mhz core with the X1800XT using 625mhz and the X1900XTX 695mhz! So chances seem good of getting 600-650mhz (a 20-30% increase) but of course nothing is certain when o/c'ing. The main thing is whether both stock or o/c'ed the X1800XL should not yield performance any slower than the 7800GT. Again FWIW all X1800 use 16pipes.

 

thanks austin again
well that seems like what i wanted to hear then. as long as im not getting any less performance then ill be happy.

 

oh noes, im getting a bit concerned now. all over the place im reading that the x1800xl is poor performer when next to a 7800gt
up to 10fps slower with fear etc. am i doing the right thing by getting the x1800xl to replace the GT?

 

Well I've played FEAR @1280*960 with 2AA, 16AF, pretty much everything on max with FPS of 50 avg & 140 max which I'm very happy with (thats on stock BTW). Also I've seen some Xl's clocked to 700/1500 which is very Impressive (Too bad my core craps out at 550MHz :/).

But if you worried that the XL won't preform aswell or it won't clock well save some more and get a 1800 XT 256, OCUK has a Sapphie one for $217 this week only thats like £5 more than the XL price and one hell of a preformance increase.

With a 50mhz core increase and 350Mhz memory increase on my card I managed to get my stock 3Dmark 05 score up form 7.5k to 8.5k, so with a XT you'd be in heaven

-Fr4nk

 

im not buying new, the x1800xl is basically costing me nothing to move to. maybe a tenner if that. so its not a cse of saving more cash or ill be without a puter

 

Ah, in that case you best get looking around for some XL's or XT 256's

 

i think xt's are still out of my budget.
it was the xl i had my eye on. but im getting so many conflicting reviews on the web its insane. some say the gt is better but thats down to the price mainly, but they dont take away the price element so they favour the GT. and then ive read the performance, some say theyre the same, then the xl will pull ahead and the majority say the GT batters the xl