question about GPUs

[forkbomb]

May I ask you what is the problem with the memory of those cards?
I read somewhere that there are different types (samsung, Hynix, ...), but I don't know if it's a thing to consider when buy the gpu, and why.

Also, what do you suggest to buy today? rx 470 or 480, and 4Gb or 8Gb?

I'm planning to build my first rig and what to have as many infos as possible before spend my money!

Thanks

[Vann]

If you are looking to build a 6+ GPU rig, the best cost per hash and power consumption is with the 4GB RX 470 / RX 570. ~900W at the wall for a 7 card RX 570 rig is possible with bios mods. The VGA memory brand only affects how easily the card overclocks. Most prefer cards with Samsung or Hynix memory which uses high quality chips that overclock well. With the lower priced 4GB RX 470/570 you have a better chance of getting a GPU with a lower tier brand memory, but it really isn't much of a factor.

[forkbomb]

If you are looking to build a 6+ GPU rig, the best cost per hash and power consumption is with the 4GB RX 470 / RX 570. ~900W at the wall for a 7 card RX 570 rig is possible with bios mods. The VGA memory brand only affects how easily the card overclocks. Most prefer cards with Samsung or Hynix memory which uses high quality chips that overclock well. With the lower priced 4GB RX 470/570 you have a better chance of getting a GPU with a lower tier brand memory, but it really isn't much of a factor.

Thanks for this, it's really what I wanted to know!

What about the differences between 470/480? If the difference in price is minimum, what is the best choice, and why? I still see some 470 at the same price as the 480s and I really don't know why!

Thanks!

[Vann]

If you are looking to build a 6+ GPU rig, the best cost per hash and power consumption is with the 4GB RX 470 / RX 570. ~900W at the wall for a 7 card RX 570 rig is possible with bios mods. The VGA memory brand only affects how easily the card overclocks. Most prefer cards with Samsung or Hynix memory which uses high quality chips that overclock well. With the lower priced 4GB RX 470/570 you have a better chance of getting a GPU with a lower tier brand memory, but it really isn't much of a factor.

Thanks for this, it's really what I wanted to know!

What about the differences between 470/480? If the difference in price is minimum, what is the best choice, and why? I still see some 470 at the same price as the 480s and I really don't know why!

Thanks!

The difference between the RX 470/480 is the memory clock speed and typically better cooling on the RX 480/580. The RX 470 has around memory clock speed of around 7000 MHz or less and the RX 480 uses a 8000 Mhz memory clock. As I said earlier the cheaper RX 470 will have a better chance of using a lower tier memory brand. After bios mods, the difference in hash rates is around 5% - 10% between the two. If you can get the RX 480/580 for around the same price, go with that.

[forkbomb]

The difference between the RX 470/480 is the memory clock speed and typically better cooling on the RX 480/580. The RX 470 has around memory clock speed of around 7000 MHz or less and the RX 480 uses a 8000 Mhz memory clock. As I said earlier the cheaper RX 470 will have a better chance of using a lower tier memory brand. After bios mods, the difference in hash rates is around 5% - 10% between the two. If you can get the RX 480/580 for around the same price, go with that.

Thanks again, you are really very helpful!

I take the chance to ask another question: what program do you use to mine, if I may ask? I was looking at claymore's one, which appears to be the best one. Do you also think that double mining (eth+sia) is good or just is not worthed (maybe about earnings/hash decrease/life og gpu)?

[QuintLeo]

The RX 470/570 has 2048 cores, the RX 480/580 has 2304 (1/8th more exactly).
This sometimes provides more hashrate, depending on the coin - most WILL benefit some, a few (ETH is notorious) are "memory-hard" and don't benefit much if at all from the additional cores.

Memory speed is normally related to the size of the memory NOT to the card model - 8GB cards generally have 8000Mhz memory, 4GB cards usually have 7000 and a few older 4GB cards have 6600.
This specifically applies to both RX 470/570 AND RX 480/580 except that I don't think anyone is making any RX 570/580 cards with 6600 Mhz memory.
 This is a fairly small factor on MOST coins, but ETH loves all the memory speed you can feed it.

 RX 480/580 generally uses a little more power than RX 470/570, if ALL other factors are equal.

 Cooling is card-model-specific, many companies make both a RX 470/570 and a RX 480/580 with the SAME cooling system on it - in which case the RX 470/570 version will usually run 1-2 degrees cooler at the same clocks and fan setting.