Reddit reviews StarTech.com 6in PCI Express Power Splitter Cable - Power splitter - 6 pin PCIe power (M) to 6 pin PCIe power (F) - 5.9 in - yellow - PCIEXSPLIT6

That depends, are you biased towards AMD or nVidia?

Personally i prefer nVidia, so cards i would recommend that will be powered by your PSU and are equivalent or more powerful than the the GTS 250 are:

GT640, GTX 550 TI, GTX 460, GTS 450.

My XPS 8100 had a 460.

Just remember, some of those cards will require two 6pin power connections, not to worry, you just need to buy a 6pin splitter.
I can confirm this works, 9800gtx requires 2 connections.

http://pcpartpicker.com/p/xRw9wP found a case that should work better, and 450w is more then enough for that build, especially at 80+ gold efficiency.

EDIT: you're also going to need one of these or one of these for the power supply to work with the video card.

that really helped. i did a bit of digging on ebay and i was wondering if this would work too.

You could try getting a splitter like this.https://www.amazon.com/StarTech-com-PCIEXSPLIT6-6-Inch-Express-Splitter/dp/B004NNTVT6

That being said, be careful about drawing too much power, check how much supply can output per slot and how much each of the cards would consume. Take undervolting into account, but to be safe I'd probably go off non-undervolted numbers.

Is this also an option http://www.amazon.co.uk/Startech-com-Express-Power-Splitter-Cable/dp/B004NNTVT6 ?

Enclosure

If you at all see yourself upgrading to a Thunderbolt 3-enabled MacBook Pro, buy yourself an AKiTio Node enclosure. If you're like me and you're going to keep buying used/refurbished 2015 model laptops until the day you die, just pick up the AKiTio Thunder2. The former comes with a 350W PSU and a Thunderbolt 3 cable, the later comes with a 65W and a Thunderbolt 2 cable.

Power Supply Unit

If you pick up a Node, you likely won't need an external PSU.

If you pick up a Thunder 2, you'll be DIY'ing your way to the dankest eGPU this side of a Solidworks Student Edition License. The best solution our community has engineered to date is the Dell DA-2 220W wiring hack. The PSU costs $15 used (they came off of old Dell Optiplex units, so they're are millions out there on eBay), and the associated wiring bits you need to turn that puppy into a compliant PSU is another $22^1.

Graphics Card
I know very little about Workstation/Professional Grade graphics cards, but I know how to read a stat sheet. Choose between one of these three (https://www.newegg.com/Product/Productcompare.aspx?CompareItemList=449%7C14-133-645%5E14-133-645%2C14-105-068%5E14-105-068%2C14-105-067%5E14-105-067), and let somebody here correct me if I'm incorrect in my selection. I would choose the AMD Radeon Pro WX 5100, but the WX 4100 should also do (and may actually fit in the Thunder2).
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^1 Three parts needed to supercharge your AKiTio Thunder2 PSU:

https://smile.amazon.com/dp/B00VWEGKD4/_encoding=UTF8?coliid=I1WKMB149AEOE0&colid=227HDTPAA1PW1

https://smile.amazon.com/dp/B018RE44DY/_encoding=UTF8?coliid=I25QNEKJN40255&colid=227HDTPAA1PW1

https://smile.amazon.com/dp/B004NNTVT6/_encoding=UTF8?coliid=I2WIPZQP7LYVIL&colid=227HDTPAA1PW1

Hi fellow miners,

Excited first timer here.

Main illustration: https://imgur.com/mAYTeBN

This is my second attempt at building a 6 card mining rig. Since my last failed attempt (https://www.reddit.com/r/EtherMining/comments/7vr330/my_sexy_drawing_mining_rig_illustration_ps_i_am_a/) , I upgraded my PSU which gave more VGA slots. I also have ordered some splitters.

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Setup:

2x 6 inch PCI Express Power Splitter Cable

https://www.amazon.co.uk/Startech-com-Express-Power-Splitter-Cable/dp/B004NNTVT6?th=1

6x 1070 ti graphics cards

i) 3x Asus TURBO GTX 1070 Ti 8GB
ii) 1x Inno3D GeForce GTX 1070Ti iChill X3 8192MB GDDR5 PCI-Express Graphics Card
iii) 2x KFA2 GeForce GTX 1070Ti EX-SNPR White 8192MB GDDR5 PCI-Express Graphics Card

6x Risers

https://www.amazon.co.uk/gp/product/B071JNQ6F7/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1
2x EVGA 750W GQ PSU's https://www.amazon.co.uk/gp/product/B017ROH8A6/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1

Dual PSU power supply adapter

https://www.amazon.co.uk/gp/product/B0788KTZPC/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

8GB Ram

https://www.amazon.co.uk/Crucial-DDR4-2400-PC4-19200-288-Pin/dp/B019FRED60/ref=pd_yo_rr_psims_i_4?_encoding=UTF8&refRID=2DPXVKMBTBV9EDR17DVE&th=1

60GB SSD

https://www.amazon.co.uk/gp/product/B019WAWYH0/ref=oh_aui_detailpage_o02_s01?ie=UTF8&psc=1

G660 CPU

https://www.amazon.co.uk/gp/product/B015VPX05A/ref=oh_aui_detailpage_o03_s01?ie=UTF8&psc=1
ASUS z270 p

MOBO

https://www.scan.co.uk/products/asus-prime-z270-p-intel-z270-s-1151-ddr4-sata3-m2-(pcie-sata)-2-way-crossfire-realtek-gbe-lan-usb-30

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1. Am I ready to turn on the rig?
   
   
   
2. Do you reckon the 1070 ti’s are too close together: https://imgur.com/GyF8KIy ?
   
   You guys are awesome. I’m new to this community and I’m surprised to see that everyone is so supportive!
   

This may work http://www.amazon.com/StarTech-com-PCIEXSPLIT6-6-Inch-Express-Splitter/dp/B004NNTVT6

I do not know anything about trying this though. Once again, I think this may just be a short term solution.

The pcie connector only provides 12v. So you should be able to find a 12v psu and wire it to a pcie connector. For an inexpensive quality power supply I'd go with a Mean Well unit. Maybe this and wire it to something like this.

This may actually be ideal because cheaper pc psus might not appropriately handle the crossload. This has good details about the pcie connector so you don't wire something up wrong which would certainly lead to catastrophic failure.