I have 900-100 dollars to invest in my computer build - Need advice!

Here are my Computer Specs!

Operating System -
Windows 7 Ultimate 64-bit SP1

CPU
Intel Core i3 4130 @ 3.40GHz 99 °C
Haswell 22nm Technology

RAM
4,00GB Dual-Channel DDR3 @ 666MHz (9-9-9-24)

Motherboard
ASRock H81M-HDS (CPUSocket) 42 °C

Graphics
Standard Monitor ([email protected])
4095MB NVIDIA GeForce GTX 1050 Ti (ZOTAC International) 52 °C

Storage
119GB TOSHIBA THNSNJ128GCST ATA Device (SSD) 35 °C
931GB Western Digital WDC WD10EZEX-08M2NA0 ATA Device (SATA) 35 °C

Optical Drives
Optiarc DVD RW AD-5240S ATA Device
DTSOFT Virtual CdRom Device
DTSOFT Virtual CdRom Device

Audio
Realtek High Definition Audio

At this point, I’ve researched a bit about the best possible way to “build” my computer for Blender usage (especially Rendering), and from what I’ve gathered it’s that for Blender “Cycles Rendering” (and most of Rendering even with different programs) I need :

Let me know if I got it right, or maybe I missed something.

NOW, my current plan was to buy a motherboard with 2x GPU sockets (I can get a deal for I5 3570K + the Gigabyte Z77X-UD3H for only 200 dollars) and 2x used GeForce 980 Ti (each ~400 dollars), so that will be the 1000 dollars spent.

Checked 2x GeForce 980Ti power compared to mine over here - http://blenchmark.com/gpu-benchmarks (my current card renders that particular scene in 91 seconds while 2x GeForce 980 Ti would render it in 37 seconds (I also might just buy the 980 without titan since it costs about 50 dollars cheaper each and only takes 6 seconds longer, aka, 2 980 = 43 seconds).

That said, I am not yet sure if I’m getting the best for the buck that I am investing, so I would like to hear thoughts from people who know about this stuff much better than I do.

Thanks!

Hi.
I think you are right in your thoughts.
Only you be careful with blenchmark results:

But there is no doubt that 2x 980 Ti would be excellent, and a great difference with the render times you currently get with 1050 Ti. If you want a comparison between Maxwell and Pascal, I can tell you that GTX 1050 Ti is comparable to GTX 960. So GTX 980 Ti is much better than that.
Just in case I clarify that when you have more than one card, vRAM do not add up. Total vRAM available is the vRAM of the card with the lowest capacity. I’m just saying this just in case, because if you thought you had more vRAM maybe you should go to Pascal.