My old GPU's are 280x and 7950 both have 3G. Will these be sufficient as N increases over time and will I have to be re-tuning cards every time N goes up?
Depends on the coin you're mining. If you set it up to allocate 2680 MB or so (just guessing what it might be), you'll be good at lookup-gap = 2 until N=12. You'll have to fiddle with LG at that point. Anytime N changes though you want to fiddle with your settings - it's not always obvious what the best settings will be. Sometimes running a lower lookup gap and limiting the intensity (using --rawintensity) gives better performance than going with a higher LG and using all the shaders.
For YACoin at N=14, My R7 250 GB card started at 1.6 KH/sec using the OLD yacminer. After I updated the software and figured out how to configure it properly, I found settings that gave me 2.5 KH/sec. I ran with that for a month before experimenting with lowering the LG by 1 and limiting the shaders. I got an extra 8% hashrate by doing this. I will eventually be releasing a spreadsheet or web application for y'all to put your settings into to get the same kinds of results, but it won't be until the algorithms are integrated into YACMiner. I still have one performance metric to come up with a formula for, but I've got quite a bit of data for it now.
I had 4G in mining box for a while and I noticed the 7950 would occasionally start at 700+ KHs mining scrypt but my box kept crashing (memtest discovered bad stick of system ram) . What is a reasonable hashrate for 7950? Now that I am only 2G sysram I have to restart miner multiple times to get 559 KHs average (and it will remain at this average for long time [days]) , it only gets an average 500KHs on some starts and remains there. Any thoughts on why this can be consistently occuring? I just restart miner and it stabilizes at 559 again. I have not changed anything in my config (other than quota percentages) for a month or so and wonder if that time it was getting 700+ was a fluke or what or is there some relation to amount of ram. As I had to remove defective stick of sysram could this have had such a dramatic effect, I am only running single channel single stick of ram for now till I upgrade to 8G for the move to scrypt-n.
I could pull the 8G from my day-to-day normal usage box and try that and see what happens boosting miner to 8G, but my motto "Don't F with it if it if it's not broken". I will get some ram on order as soon as I can afford it.
Anyone care to donate 8G DDR2-800 (4 sticks of 2G) that they are not using? LOL.
PM me if you can make a good deal
I have over 17M MOON that I have mined and am holding atm. Holding some other alt-coins as well. Let me know what your choice to cryptocurrency is and I will look to see what I have ...