Video upgrade - 4870 1GB vs 4870 X2

[Maplicito]

Not a new build per se, rather come tax return time, I am looking at replacing my 4670 1GB with something higher octane. I am debating with myself whether I want to get a 4870 1GB card, and possibly crossfire it later, or if I want to get a 4870 X2.

I guess a large part of the question boils down to - how big an advantage is two 4870 X2's in crossfire over two 4870 1GB's in crossfire? If there isn't much of an advantage, I'll likely save money now, and get the single GPU card and crossfire it later if I feel the need - if there is a huge advantage, I'd probably just get the X2, and crossfire it later if I ever feel the need.

Right now, I'm leaning toward just getting the single GPU card, but am looking for input.

[cadaveca]

For every gpu you add, efficency drops a fair amount...I'd suggest no more than 2GPUs, and even then, 100% scaling in any app is very hard to maintain at the driver level.

I'd suggest just a single 4870x2, reference model...no more than that.

I can run GRID @ 2560x1600 on a single 4870 1GB, AA included.

[Maplicito]

Is running the two GPUs in one card a big advantage (whether it be performance, or just simply in ease) over doing it in two cards? Part of me is wanting to put out as little initial investment as I can get away with, although I suppose that's funny to hear in the same sentence as "4870 X2"

I'm not entirely convinced I'll actually need more than the single GPU, but upgrading is... addicting. The 4670 has actually ran most of the games I play much better than I expected, although Mirror's Edge has caused some hiccups at 1600x1200. I have seen one good deal on an X2 though - $500 before shipping, handling, and GST, so maybe I'll have to go that route.

[cadaveca]

On one card, means less data on the pci-e bus, as well as lower-latency between the gpus. It's a miniscule difference, but given the cost of 4870 1GB, and the cost of a 4870x2, I think that the slight difference warrants buying the single-card 4870x2.

[Maplicito]

Okay... the next question from there is - if I go the X2 route, will my 700W OCZ GameXstream be adequate, or will I be needing to upgrade that to run an X2?

I'm not running a whole lot off the power supply... the system is as follows:

Q9550 with Arctic Cooling Freezer 7 Pro
1.5TB Seagate
1 DVD burner
Stock fans on an Antec Nine Hundred case plus one 120mm fan.

Yeah... that pretty much sums up what's running off that PSU.

[cadaveca]

It should have enough juice, but without an 8-pin PCI-E connector, I don't know that it's a perfect fit. I do believe the minimum is 650w, but it's best to check @ the game.amd site to eb sure...they have a full list of supported stuff.


EDIT:

Here's the psu list:

ATI CrossFireX? | GAME.AMD.COM

[Maplicito]

If I used a 6 pin to 8 pin converter, would that be adequate? Or is that going to leave me with some problems? Or a molex to 8 pin converter?

[cadaveca]

Can't say...your psu isn't on the "approved" list...but that doesn't mean it won't work...and I don't have either component to test it out for ya.

[Soultribunal]

I might be a little wary on the PSU, it is twin railed but only 18A/rail....dunno what the X2 needs but that seems taxing when you combine it with the rest of your system (PSU guru's step in at anytime lol).

A PC Power and Cooling 750w has 60A on a single Rail, which would provide more than enough power for that Card and System.

My two cents at least,
I've always gone for Single railed High A PSU's for my needs.
To each there own,

ST

[Maplicito]

Well... whichever card I end up with, I'll give it a go... worst that can happen is I need to get another PSU. Thanks for the advice.