Your 750 is 4 years old tech. It would still be able to mine a cryptonote coin but it's not very efficient - it gets obliterated by a single Vega 56. It would be akin to trying to offer Uber services with a Chevy Nova.

Don't bother with Monero. You might be able to do ETN. It probably won't break even with electricity on Ethash.

As others have said, you should do more research - there are tons of old threads detailing what a 750 used to do.

As mentioned above a swamp cooler (evaporative cooler) should be able to assist with raising the humidity for little cost.  If you're moving a lot of air consider buying an static air discharger/ionizer.  Fast movement of air can lead to increased charges, especially if the air has particulates.

I killed a SCSI hard drive a long time ago when the Santa Ana winds were kicking up and humidity dropped to single digits. I wasn't even moving, I simply touched the drive and fried the logic controller on the board. Now I won't touch my miners on windy days.

If you had a free rig ready to mine, a video card bought now would take somewhere between 5 months and a year to break even. If you want a profit in 120 day you've high.

While I don't believe a rig costs $1100 as noted above, a good 6 card setup will run you about $250 without the card, leaving you just enough for 1 1080TI or maybe 2 1070s if you can get some cheap models. $250 setup would be a decent 6 card Mobo like H81 BTC, 4-8GB DDR3, small SSD 64-120gb, and a high quality PSU which should last you 10 years of mining like an EVGA G3 850.

The whole $1k setup should break even between 8 months to 1 year barring any crypto circus like we saw in March to June.

There is no quick profit in mining, but there is quick winnings (and losses) in crypto trading. You could buy $1k of ETH or BCH and could possibily see your investment double in 2 weeks - you can't even mine 1/10 of your investment in that time - but of course it's pretty hard to lose mining unless you're in California.

As somebody who had (including the wife's) collectively 27 insurance policies from property liability to death to disability I can tell you most of the terms on home-owner property insurance typically state that anything in excess of 10K in niche field is not covered unless you have a specialized rider policy. I found this out the hard way after losing about $40k in a home burglary and my wife's wedding ring wasn't covered because we didn't have a special policy. I have over 250k of "stuff" that most normal people wouldn't have including Lego collections and tools and of course miners.

Each insurance policy is different, but if you want 100% assurance you have coverage you either need to have an adjuster come out and get a letter in writing or document in video/photos the items you want covered and get a written notice affirming such. Taking somebody's word over the phone is useless.

You plebs mine $30 and this guy will disappear.... it's a SCAM. He has no reason to stick around and pay anybody.

The amount of sheer ignorance posted thus far is like looking at all the newbie posts asking if a 1070 can do 57MH/s on ethash.

Running one or 2 video cards at home most likely will not be the cause of your demise. Odds are you're more likely to get hit by lightning.

increase the number of cards, however, to a small farm and you are now getting higher particulate benzene, toluene, chlorobenzene, ethyl-benzene, xylene, styrene, benzaldehyde, and trimethyl-benzene in your air - especially if you don't have fresh air intakes.

While some of these chemicals occur naturally, the amount given off by PCBs as volatile organic compounds is multiplied by the number of devices being used as well as operating conditions like humidity, voltage and ambient temperatures.

I bought high quality VOC meter to monitor the air at my farm.

For myself, I run any new cards I get in an outdoor or ventilated setup for 2 months before putting them in a place with a lot less ventilation.

While a space heater may give off heat from warming resistive coils, it doesn't give off nearly as many VOCs as new carpet or a new video card does.

First thing is to identify what motherboard is being used. The OP PMed me and said the addition of the 8th card causes variation of rate from 28 to 14 and back. Knowing the motherboard and bios revision would help.

Make sure to have virtual memory high enough. I would do at least 24576 for 6 card, some multiple of 4096 thereafter if using 8 like 8 x 4096.

The Power supply make be adequate, but if not cabled properly to the risers that can be an issue as well. Make sure no more than 2 cards per Molex or Sata chain. Splitting a 6 or pin cable is usually safer than using those two thinner cables.

Opening up task manager will usually help prove CPU is not pegged at 100% on a core or something is not stuck in the background. Using Afterburner helps show if the GPU core clocks are throttling and why they might be throttling.

Most important is to know the mobo model though.... else we're all just guessing.

20 is probably the fastest those old Tongas will get these days.  I was able to mod my 380s but ended up selling them. Nerdralph has a good post here: http://nerdralph.blogspot.com/2016/09/advanced-tonga-bios-editing.html

Unless somebody is willing to give exact models of mobo and cpu having issues I call BS. I've used everything from a Sempron 140 to a I7-2600K for GPU mining since 2011. The only time I did see any bottleneck was when I used the Sempron because it was single core and creation of DAG is CPU instensive. When you use single core CPUs any operations other than mining (like a Teamviewer connection) does slow down hashrate.  I have frequently swapped back and forth between Celeron 530 and I5-3470 and not had any difference in share submission rate with Bitcoin, Monero, or Ethash (yes I mined Bitcoin back i the day). The caveat being I was not CPU mining as well.

If you plan on CPU mining as well it makes sense to go with an I5 or I7 or Ryzen equivalent. Just make sure you leave a core free to handle the OS and share submission for the miner.

CPU choice does effect the system memory speed utilized and could possibly alter the PCIe lanes if the board manufacturer does something wonky so there's always that, but a Celeron 3930 should be more than sufficient for a 8 card rig that's only GPU mining. You might see a small boost going from HD to SSD since disk i/o does slow down mining especially if running on low memory. Unfortunately DDR4 and flash memory prices are double what they were last year.

Short of going for a single core ancient Pentium, the money would be better spent on a higher end power supply. Better ripple control and consistent power keeps cards mining reliably.

You will not be doing any kind of mining with a SFF system. The PSU is too weak and there is not space for a video card.

You could do a frankenstein rig by moving the guts to another case or even an open system but you would still need a more powerful PSU to power the strain the CPU/GPUs would endure.

Back in the Bitcoin GPU mining days I used Dell SFF systems and used another PSU and GPU ribbon riser to mine. With the arrival of USB Risers and dedicated mining boards it just makes sense to build a new system unless you already know how to tinker with hardware.

It's a scam already.  Sheesh this thing has been spammed 6 times in the last 5 pages. It's always the noobs looking for a shortcut...

Part of the mining experience is learning about your coin - not just how to make money. Using a good calculator like https://etherscan.io/ether-mining-calculator would show that you should be earning about 0.74/mo at present rate assuming an effective 130 MH/s rate. Factor in pool fee and Claymore fee and you can shave off a little more.

The calculator you are using is making serious mistakes in calculation - scroll to the bottom and read the fine print. It assumes 19 second block time - we're way higher than that. It also assumes we're 5 ETH reward when we are at 4.95 and will drop to 3 soon.

By using the mail system you are committing a felony right there which is good for 5 years and nice hefty fine, not to mention also possible fraud charges that Zotac or the seller might pursue.

Contact the seller and ask for a new invoice. If they don't respond, contact Zotac and show them the paypal or credit card statement. Zotac should be able to estimate the manufacture time and should work with you.

Swapping serial labels makes you an asshat and you're asking for negative trust just for considering that kind of unethical behavior.

Well the card manufacturers went out of their way to supply us with crappy dedicated mining cards that are effectively useless for resale when the next gen cards come out (what gamer is going to use a DVI output). The only way they can guarantee their ROI on designing those things is to guarantee sales by saying "hey, we have cookies, err Samsung memory".

Still trying to figure out what is worse... nvidia pulling this crap with RAM switching or AMD CEO blowing off GPU miners as a fad.

I think it's pretty much confirmed from the scrypt mining days that if you push the memory too hard you will in fact damage it. It's pretty hard to kill the GPU core because you will usually blow out the voltage regulation/caps well before that. Memory degradation did occur during scrypt days pushing those 7970s/280x to high mem clocks.

If you're seeing artifacts you should back down. No point in submitting incorrect shares.

I have an old AGP Radeon AIW that has a lovely RGB pattern thanks to toasted memory - thankfully GDDR5 is a little more robust, but not by much.

This is where new users make their mistake - they are only considering fiat ROI. People buy miners as a hedge against the risk of buying a crypto and then having that crypto lose against fiat - thus losing money. If ethereum goes to 500 then you are correct you will make fiat ROI earlier (assuming more people don't pile on mining which of course they will if the price goes up).

But consider is the risk of buying all the hardware and maintaining it worth it to basically earn "free" video cards and motherboards. For some it is worth it.

For others they are willing to risk that same capital investment directly into the crypto itself. There is no tangible safety if their crypto goes to 0 value, but the gains are sometimes a magnitude higher when buying coins directly. The opportunity time is essentially negligible when buying fiat directly.

New users should consider what level of risk they should be taking. In the example above, if ethereum shoots to 500 tomorrow - a person who buys today at 290 will always come out ahead of somebody who mines even if POW stays alive for 1 year - their fiat gain is instantly realized within 24 hours - they can choose to take profit or gamble on higher rewards... a miner does not have that luxury and with consideration of how eth attracts all the stupids (because people think it's the most profitable) the difficulty will just continue to cut into the miners profits.

Real crypto ROI is whether it would have been better to just buy crypto at a certain point instead of buying hardware. For many ASIC miners they may ROI in fiat but lose in crypto ROI because they would have more coins in hand if they bough directly instead of buying a miner.

You're going about this all wrong in my opinion. Start off small, but start RIGHT NOW. Buy just one card and have it sent to you ASAP. If you have a basic PC mine on that first.

The fact that you're even considering an I7 CPU or 32GB of RAM (the wrong type as well) means you're jumping without looking where you're jumping to... this only leads to errors that will make you regret starting.

Start now with a simple but modern card - any brand of GTX 1050, GTX 1060, RX 560, RX 580 is fine for learning. These cards all have tons of guides out there and even some youtube videos that can hold your hand on how to build a whole rig. Once you understand how to mining, difficulty, pools, latency, wallets all work then jump in if you're stilll up to it.

If you want to make 2-3k per month you're looking at spending at least 20K right now factoring in future difficulty jumps and no price increase.

I've been mining since 2011 and I have sold off most of my cards in the last 3 months for insane prices and bought an insane amount of crypto compared to what I would be able to mine. I'll buy used cards in bulk when the next crash finally sets in. I might be wrong but I think getting in now is a mistake, except for maybe learning with 1 card or 2.

I just had an old order for an EVGA 1060 6GB SSC ship finally (came in stock) and it has.... wait for it... Hynix.

Gets about 265 sols on ZEC which I'm OK with. I'm gonna use it as my gaming card next month anyways.

Looks like card manufacturers have diverted all their Samsung chip allocation to their dedicated mining cards - so that is the only selling point for those pure mining cards. You want that extra 10 to 20% hash you buy a dedicated mining card - otherwise stick with the consumer market and consider yourself lucky if you get Micron.

Looks like almost all the 1060 models are in stock everywhere now and the 1070s are starting to trickle in.... still no $100 1070s on Craigslist though 

If there's an announcement and it's promising, you're already too late with your $500.

You're basically gambling.

If you're going to gamble, pick the riskiest bet which is to mine a non-promising coin and hope it goes up in price. Find the one with the lowest difficulty.

As for using your laptop, unless you're using a gaming laptop you would be a fool to mine on a laptop. Gaming laptops have decent copper heatpipes for the CPU. Don't even try GPU mining or you'll be out a $1500 laptop.