I am currently mining at btc guild with 3 gh/s and getting a stale rate of about 2.3%. If I mine with deepbit, will my stale shares be less?
Depends on the cause of those stales. You can just try and find out
In my experience, absolutely there will be fewer stale shares. At least 50% less if not more. BTC Guild grew very quickly and uses stock, or nearly stock push pool code on each server with some bitcoind modifications of questionable value, and distributes pools around the US and EU and then syncs them up for total pool payout on blocks found. This has resulted in pool servers becoming overloaded, dropping connections (often 10 or 15 seconds) or leaving the miner without a response for new work [long poll or main RPC call] leaving the miner idle. I am not trying to knock BTC Guild [I think they are second only to Deepbit when both are running well], so, once that pool is in good shape again [supposedly the weekend of 7/10], you can do more direct comparisons. Both pools have similar feature sets with BTC Guild taking on a variation on the theme making them different than other pools [just as Deepbit is and was different than other pools when started]. Weigh the options, test a little and decide for yourself
. Personally, Deepbit, over the last many weeks has been by far the most stable pool out there [thus, losses due to idles, outright connection loss, and increased stales from other pools tends to offset the premium 3% fee ... and some people have attacked the fee as too high, but with maximum availability as opposed to other pools, features, etc, this is clearly a working model and "supply and demand" has clearly justified the 3% which I pay without regret]. I don't know how deepbit distributes the servers for the pool [there has to be multiple, right Tycho?], but however it is being done, it is by far the most reliable of any large pool out there.
Last, it is usually a good thing to have accounts at two or three pools to work with; occasionally every book has gone done and every pool has gone down for a significant period of time [even Deepbit, but always recovered better than before and made up for the one time long outage by a large fee reduction which was not required and simply great customer service]. It is also good to, now and then, test the other pools to see what is working for you at any given time [every five day or whatever, connect to another pool for a statistical sampling to determine what your submission rate is, % stale and of course if there are idles or RPC connection issues, so you know whether to reevaluate your primary pool, or more likely, know which is your best backup option should an outage or unstable situation occur]. If your GPU utilization is cycling (due to receiving no work or outright RPC communication failures), in particular enough to cause the temperature to change by more than a couple of degrees frequently, that is a sure sign to run ... it is very hard on your GPU, especially since it is running 24/7 at 99-100% unlike it would for normal gaming [frequent temperature fluctuations, especially a the higher temps of high utlization causes fatigue wear and tear leading to reduced life, likely significant, of the hardware]. Deepbit leaves me with pretty constant GPU usage, and even with a pool restart of something now and then, one blip is a non-issue.
For me, in spite of my ventures elsewhere, Deepbit remains my pool of choice and is BY FAR the most stable in all respects mentioned above. Every attempt to mine elsewhere for backup testing has shown deficiencies in the pool within a couple thousand shares per miner, which is what is required to get a reasonable idea of stale rates anyway.
As usual ... I am verbose