R9 290 riser, psu

bata88bata88 Member Posts: 18
edited August 2016 in Mining
My psu have 2 molex cable,i want to use powered risers, i read somewhere r9 290 drain about 4A on the 12V, my psu can supply 15A with the first molex, and 15A with the second molex. So i can supply 3 r9 290 with the first , and 3 r9 290 with the second?(this psu only to motherboard,cpu..., i have second psu to the GPUs.

Comments

  • stoonstoon Member Posts: 337 ✭✭✭
    Most powered USB risers have a Molex to SATA power adapter. As long as your PSU has SATA power connectors you'll be fine.
  • bata88bata88 Member Posts: 18
  • wirelessnet2wirelessnet2 Member Posts: 385 ✭✭✭
    I would strongly suggest against using SATA to Molex adapters. The fire hazzards are real guys, dont pass it off as nothing @bata88
  • bata88bata88 Member Posts: 18

    I would strongly suggest against using SATA to Molex adapters. The fire hazzards are real guys, dont pass it off as nothing @bata88

    Thanks for the warning ,adapters are dangerous?
  • wirelessnet2wirelessnet2 Member Posts: 385 ✭✭✭
    @bata88 yes they do catch fire. Not super often, but they do.
  • core16core16 Member Posts: 16
    @wirelessnet2 So what would you suggest? A direct molex connection (must I buy molex cables to replace the sata adapter usually provided or do you know of a seller that includes it)? I've read that you shouldn't have more than one rx480 per sata chain - would this be the same for a direct molex connection or not thanks to the higher current rating? Thanks
  • ethfanethfan Member Posts: 458 ✭✭✭
    The official specs for the sata power connector is max 54W (for 12V). If there is an adapter that converts two sata to one molex that should be more than adequate since theoretically the riser should need to supply only 75W. I have only seen the opposite (in fact I have a few) where one sata converts to two molex.
  • oAPMooAPMo Member Posts: 97
    If you have a psu with no more warranty, simply cut the plastic on the molex cable that comes from you psu and solder the pcie riser power cable to it, I got sick of molexes, they cannot maintain perfect contact so either cable burns or receives unstable power. So this is the best choice, then connect to molex and last is sata, they can't output as much power. Oh yeah after soldering the power cables together, the cable was at least half of its temperature, before it was hot as fuck, it just shows how bad are molexes at maintaining perfect contact.
  • WoolingJumperWoolingJumper Member Posts: 32
    @wirelessnet2 how many risers are you suggesting to connect to a single Molex to PSU string? 1 string can connect up to 4. I tried 3 risers in 1 string and it gets so hot that I literally unplugged in in just 5 minutes. I am talking about RX 480 in this case. Some says it pulls more power from the risers compared to earlier model AMD cards.
  • ethfanethfan Member Posts: 458 ✭✭✭
    @WoolingJumper, if the PSU cable is the usual 18 AWG size even two 480 is inadvisable.
  • WoolingJumperWoolingJumper Member Posts: 32
    @ethfan I have a 1000 watt 80+ Gold Corsair PSU. What I did is, 2 risers in 1 molex to PSU, since I have two it covered 4 risers and then 1 SATA string each to the remaining 2 risers.
  • oAPMooAPMo Member Posts: 97
    Guys just solder it, I don't know how many you can put there but I have 2x r9 390 running each at least on 300W and 1cable for both cards goes to the psu's molex string (but not through the molex, soldered before the molex connector) and the cable from the psu is cold, the one from the riser is maybe about 10C warmer (can use thicker cable if it gets too warm)
  • wirelessnet2wirelessnet2 Member Posts: 385 ✭✭✭
    well I can't speak for the RX 480s. I have 3 R9 390s on a single molex chain, and its not even warm. I dont really know what to do unless you guys want to solder, but I do know using a SATA to Molex adapter will most likely ruin your day @WoolingJumper @core16
  • bata88bata88 Member Posts: 18
    I have warranty, so i don't want to solder it. What can i do?
  • oAPMooAPMo Member Posts: 97
    @bata88 whatever you do, don't connect to sata, go through molex only. If you can connect them to have proper contact, there shouldn't be a problem. When you do connect, check if the molex pin doesn't come out on the back, if it does, push it back.
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