I disagree, but then again I just upgraded from an SLI 8800GTS G92 system that had full waterblocks on each card so...

Full blocks cover VRMs, but then you're stuck with those cards. When upgrade time comes, you have to upgrade blocks as well. So it depends on what kind of blocks you want.

I got about 25mhz more than I could with stock cooling, but yes, the VRM temps are the limiting factor. (On the 1GB 6950s, VRM cooling is sub-par anyway and was likely also limiting with the stock cooler.) If I got / fabbed a massive copper heatsink that fit under the aftermarket cooler I could probably get a little more out of it.

Water would likely run you cooler, so long as you could also cool the VRMs.

I have a Accelero Xtreme Plus (similar cooler) on my 6950 1GB (similar PCB to 6850) on my bedroom computer. Had to re-set the heatsink 4 times or so not due to any mounting difficulty with the HSF portion, but to changes and interference with other heatsinks (ramsinks, vrmsinks) on the board.

I've OCed it a bit, but can't get much farther than stock because the VRMs get way too hot. It runs about 15c cooler (at 860mhz core) than the stock cooler (at 836mhz core), but it is way quieter - fades into the background. The stock VRM cooler, which isn't integrated into the HSF like it is on the 2GB models, would get VRMs up to 120C and higher at stock clocks and voltages with OCCT. Replaced with the alu ones that came in the VR001 kit and now, with power threshold set to 10% above, at OCed settings, VRM temps top around 100c.(*) Core tops around 70c at the hottest part of the day, as opposed to 85c with the stock cooler.

Probably not worth the money unless the rig is physically near you so you have to hear it.

(*) VRM temps may not be reported accurately.

There were 1MB boards? Maybe the code fits in that space, but you might have to run at 640x480 8bpp or less to reduce the framebuffer size and make room...

That said, as long as core clockspeeds are the same, there won't be a hashrate difference between 1GB, 2GB or 4GB boards. The data being hashed is very small, and the hashes (except those with difficulty at least 1) aren't stored. There's no reason to concern yourself with RAM size unless you intend to play games with very high AA or high resolutions.

Bitcoin mining doesn't need these huge amounts of RAM. With no other differences, either should give the same hashrate.

I got a 5770 for $115 for a rig that doesn't have enough PSU power for a second 6950. Overclocks fairly well - have it at 920mhz and still plenty of headroom. Gets 175Mh/sec.

It's a worthwhile upgrade if you are intending to game on your rig, as the 210 is abysmal at that. This also depends on the games you play and at what resolutions you intend to play them. If you're buying it just to mine, ...look at a used card or something

Only if you're not paying for electricity.

The drivers aren't bad - why people still say that is likely because the installer looked like crap. It still looks bad, and there are plenty of issues installing drivers for older ATi hardware, but current AMD videocards tend to work well...though there are sometimes still installer problems

People equate driver tweaking UI == driver

It very well could be slots too close problem, can't get enough airflow to the top card. It's what it sounds like.

One of my cases (Antec P180) has decent ventilation, but my fan installation and speed choices were designed when I ran a dual 8800GTS G92 system on water. And that system has a 6950 1GB on air - thing is, the 1GB card has a crap heatpipe cooler that barely copes (the 2GB model has a way better reference cooler). With the case side off, it'll bluescreen after 3-4 days of hashing...thinking it eventually gets over the heatpipe's ability to remove heat; I am assuming it's thermal runaway. Solution was to order an Accelero Xtreme Plus cooler...it'll also solve the noise issue (this is my in-bedroom computer and is currently pretty loud...) - it's in the mail now.

Except everyone will do that, then...

Barring external influences (popularity, etc) once BTC generally becomes cost prohibitive to produce, I don't think it'll fall below that line, or if it does, it won't for very long.

Why would you think that? It's been widely reported that reference 6950s have identical PCBs to 6970s, and there are various unlock methods available. The chips seem to be identical, with perhaps better bins on the 6970s but this isn't proven. 6970s are run at higher voltage by default, though. I've unlocked two of my 6950s. (Have a 1GB model for a specific machine and there aren't any known public unlocks yet, if ever - this one MAY have hardware changes to prevent it.)  Will unlock three more 6950s after they're delivered.

Certainly a local problem - I can buy 10 from a retailer in a transaction, and many retailers have 6950s and 6970s with at least that much stock.

If you feel safe hacking the slot and having little retention for something with more weight than what is typically in an x1 slot, go for it

True, but the connector must be the right size - and cards used for mining on the market use a physical x16 connector.

This is on a 1GB model (used in 32bit machine, needed memory space for main memory vs GPU memory and don't use above 1920x1200).

With -w 64, I get ~250Mh/sec.

With -v -w 64, I get ~295Mh/sec, although the deviation seems to be less and peaks higher than -v -w 128, so I think I'll stick with that now.

Also how are you running memory so low? Do you mean 1155? Or is it really that low? (Edit: Seems to be 1155. At 1100 I start losing ~5Mh/sec. At 1150 I get the same as 1280, so it's sticking there.)

Install card. Install drivers. Go for it. There really isn't much else to do but that.

No, it's not. It is if the machines had no purpose for me other than BTC, I didn't get epic deals on the hardware, and I was starting from zero balance. I already had a small amount of BTC to start with, and not only that, I already had some of the hardware and with its daily active use doing other things than bitcoin, already consider it paid off. It's perspective, not hard numbers. The *new* hardware I bought I will consider paid off. And again, this is considering worst case projections...things aren't looking quite that bad.

But of course people will argue stupid shit here. Which I'm perfectly fine with actually, there's been some interesting viewpoints brought up because of it. At least you read the post and put some thought to it.

On the Windows box, I use Sapphire TRIXX...controls the fan well, doesn't require special unlocking techniques, but has a PITA registration requirement to download. Slight overclock gets me ~295Mh/sec on a single HD6950 1GB, 850/1280, -v -w 128.