Hardware question from a newbie

Hi all

I've recently been thinking about upgrading my (and by upgrading I mean getting a brand spanking new) pc.

A few weeks ago I started looking into Bitcoin. Being a banker by profession it fascinated me, and aligned perfectly with my love for computers and the financial sector.

I thought this would be a great chance to kill two birds with one stone, get a new PC, and indulge my fascination with crypto currencies and try out building my own rig (would also be a first) and indulge in some mining.

My point in giving you this background is that I realize it may not be the most profitable thing to do now, but the combination of motivations makes it interesting for me.

So, my question revolves around hardware for my new build. After trolling the hardware section of the forum I decided 7970's were one of the agreed top choices for a GPU. I'm considering 2x of them, but would like to have room to upgrade to 3 or 4 if I really am enjoying myself. I would also like to be able to game on the system from time to time (nothing too intensive, but it would motivate a decent CPU and some decent RAM).

So, I've pulled the specs for the following motherboards, cpus, and gpus. And would really appreciate anyones views on which would be good/adequate.

I've shown the price (in ZAR (South African Rands)) to illustrate cost differences. Yes its more expensive than the US. Please also avoid just saying 'the most expensive option is the best one'... I'm sure thats why its priced that way. I'd rather comments that say something like 'well the more expensive one is marginally better, but not worth the extra price'.

This is already long enough, so the pieces are (last thing, I've included AMD and intel chipsets so please advise which you think is best):

Motherboard –

R2,222 Gigabyte ga-990FXA-UD5 AM3/AM3+ mb ( black ) - with 3-way CrossFireX/SLi support , Driver MOSFETs ( Integrated VRM Components ) , Cloud OC ( OverClocking via browsing capable mobile device ) , UEFi dual BiOS + Ultra Durable 3 ( 2 layers copper PCB , Ferrite core choke , solid cap + low RDs(on) MoSFET ) + on/off charge technology ( charge usb device when PC is off ) , AMD 990FX/sb950 chipset , 4x dual channel DDR3-2000(O.C)/1866/1600 , 10 ( 8x internal SATA6G + 2x external powered e-sata ) with raid 0/1/0+1/5/10 , on-board ieee1394 + ALC898 Dolby Home Theater 7.1 audio ( 108dB Signal-to-Noise ratio playback ) with optical s/pdif out + Realtek RTL8111E gigabit lan ; 5x pci-e 2.0 16x ( 16x+16x+8x+4x+4x ) , 1xPCi-E(1x) ,1x pci , 2x USB3.0+ 8x usb2.0 with 3x USB power boost , support optional serial port add-on cable - atx , 1x PS2 only for kb

R1,591 Gigabyte ga-990FXA-D3 AM3/AM3+ mb ( blue ) - with 2-way CrossFireX/SLi support , Cloud OC ( OverClocking via browsing capable mobile device ) , UEFi dual BiOS + Ultra Durable 3 ( 2 layers copper PCB , Ferrite core choke , solid cap + low RDs(on) MoSFET ) + on/off charge technology ( charge usb device when PC is off ) , AMD 990FX/sb950 chipset , 4x dual channel DDR3-2000(O.C)/1866/1600 , 6x SATA6G with raid 0/1/0+1/5/10 , on-board ieee1394 + ALC898 7.1 audio ( 108dB Signal-to-Noise ratio playback ) with optical s/pdif out + Realtek RTL8111E gigabit lan ; 4x pci-e 2.0 16x ( 16x+16x+4x+4x ) , 1xPCi-E(1x) ,1x pci , 2x USB3.0+ 8x usb2.0 with 3x USB power boost , support optional serial port add-on cable - atx , 1x PS2 only for kb

R2,759 Gigabyte ga-Z77X-UD5H-WB wifi : all-in-one LGA1155 mb ( black PCB ) , support LGA1155 / XEoN E3-1200 cpu - with bundled bluetooth 4.0/ dual band WiFi Pci-E (1.0) card + onboard O.C ( power+reset buttons + LED debug display + voltage read points + OC-PEG + BiOS switcher ) + 3D power engine with 12 phase power design for 4x dedicated power zones ( CPU/GPU/memory/VTT ) + 333 onboard acceleration + lucidlogix virtu MVP + 3D UEFi dual BiOS + mSATA slot ( SSD caching ) for Rapid Start Technology + Ultra Durable 4 ( humidity protection via Glass Fabric PCB + electrostatic protection + power failure protection via dual BiOS + high temperature protection via all solid cap + low RDs(on) MoSFET ) + Lan optimizer + on/off charge technology ( charge usb device when PC is off ) , with EZ Smart Response for SRT , support intel SCT+ Rapid Start Technology , crossfire + SLi ready ; intel Z77 chipset , 4x dual channel DDR3 2400(O.C)/1600 upto 32Gb , 11x s-ata with raid 0/1//0+1/5/10 ( 1x mSATA for SSD + 5x SATA6G + 1x eSATA + 4x SATA3G ) , on-board dual-display VGA with Quad -output ( HDMi + DVi + d-sub+ DP ) + Realtek ALC898 X-Fi Xtreme Fidelity and EAX 7.1 audio with optical s/pdif out out + dual gigabit lan (Atheros + intel) + BT4.0+ dual band WiFi ; 1x PCi + 3 x pci-e (1x) + 3x pci-e 3.0 (16x @ 16x+8x+4x) , with iEEE1394A+ 4x USB3.0 + 2x USB2.0 - 1x PS2 - atx

R2,799 Asus Maximus 5(V) Formula : all-in-one LGA1155 mb , support LGA1155 / XEoN E3-1200 cpu , with mPCi-E combo + Fusion Thermo watercool ready + 8+4+2 phase power design + dual intelligent processors3 ( for TPU+ smart DiGi+ii VRM ) + Fan Xpert 2 + EFi mouse-controlled bios + FBT+ SRT+ SCT+ RRT+ Rapid Storage+ Rapid Start Technology + SLI/CrossfireX ready + USB BIOS Flashback button ; intel Z77 chipset , 4x dual channel DDR3-2800(o.c) with XMP support upto 32Gb , 10x s-ata with raid 0/1//0+1/5/10 ( 6x SATA6G + 1x mSATA + 2x SATA3G+ 1x eSATA ) , on-board dual-display VGA (with HDMi + DP) + SupremeFX iV X-Fi THX 7.1 audio with optical s/pdif in+out + intel 82579V gigabit lan + 2.4/5GHz dual band WiFi + BlueTooth ; 1x mini-PCi-E , 3x pci-E(1x) , 1x pci-e(4x) , 3x pci-e 3.0(16x) for Quad-GPU SLi/CrossfireX , with 4x USB3.0 + 4x USB2.0 , USB3.0 with UASP (USB Attached SCSI Protocol) - atx

R3,599 Asus P8Z77 WS : all-in-one single socket LGA1155 mb , support LGA1155 / XEoN E3-1200 cpu - with 3-color LED for OC status + Diag. LED + 16+4 phase power design , dual intelligent processors3 ( for TPU+ smart DiGi+ VRM ) + Fan Xpert 2 + EFi mouse-controlled bios + FBT+ SRT+ SCT+ RRT+ Rapid Storage+ Rapid Start Technology + SLI/CrossfireX ready + USB BIOS Flashback button ; intel Z77 chipset , 4x dual channel DDR3-2800(O.C)/1600 with XMP support upto 32Gb , 10x s-ata with raid 0/1//0+1/5/10 ( 4x SATA6G + 4x SATA3G + 2x eSATA ) , on-board VGA with DVi + Realtek ALC898 DTS 7.1 audio with optical s/pdif out + dual intel 82574L gigabit server lan ; 2x pci-e(1x) , 4x pci-e 3.0(16x) for Quad-GPU SLi/CrossfireX , with 4x USB3.0 + 4x USB2.0 , USB3.0 with UASP (USB Attached SCSI Protocol) , 1x PS2 – atx

Chipset –

R2,121 Intel ivybridge lga1155 i5-3570K - Quad core / 4threads , 3.4ghz box cpu / 3.8ghz turbo boost , unlocked clock multiplier , 22nm , VT-x+ AES-N + AVX , no vPro , no TXT , no VT-d , built-in dual channel DDR3-1600 memory controler , 25.6Gb/sec memory bandwidth , built-in HD4000 graphics ( 16EU , 650/1150mhz , dual stream video decode + HDMi ) , 6mb L3 cache , 77w - Quick Sync Video + InTru 3D + Insider + FDi + Clear Video HD + Dual Display + wireless display Capable - don't support Hxx/Bxx chipset
R2,199 Amd vishera / socket AM3+ AM3+ , FX-8350 - 8x cores ( 4.0ghz box cpu / 4.2ghz turbo core ) Black edition , unlocked clock multiplier ; 384k L1 + 4x 2mb L2 + shared 8mb L3 , intergrated dual channel DDR3-1866 memory controller ; 32nm , 125w , 4000mhz HT3.0 HT3.0 , with PVT - box cpu ( with fan )
Gigabyte GFX –

R4343 Gigabyte GV-R795WF3-3GD - PCi-E 3.0 , with WindForce3x - 3 fans design with Triangle Cool , Ultra Durable 2 ( with Low RDS(on) MOSFET + Low Power Loss - Ferrite Core Choke All-Solid Capacitor ) , gold plated HDMi connector , 28nm , support HDMi 1.4a + Displayport 1.2 with MST , support 6x daisy-chian display via MST hub , support Eyefinity + DirectX 11 , crossfire-X , built-in HDMi codec+7.1 audio , 1080p HDCP Compliant , 3Gb 384bit 4 channel DDR5 , 32RoPs , 264Gb/sec memory transfer ; 3.79TFLoPS , 2048 ALU/stream processors ( pixel shader engine + vertex pipelines ) , 128 texture unit , core/memory : 800/5000mhz , HDMI+DVi+2x mini DisplayPort , with miniDP to DVi converter - require 2 x pin power connector - full retail pack

R4343 Gigabyte GV-R797d5-3GD-b - PCi-E 3.0 , 28nm , DirectX 11 , crossfire-X , 3Gb 384bit 4 channel DDR5 , 32RoPs , 264Gb/sec memory transfer ; 3.79TFLoPS , 2048 ALU/stream processors ( pixel shader engine + vertex pipelines ) , 128 texture unit , core/memory : 925/5500mhz , HDMI+DVi+2x mini DisplayPort , with HDMi to DVI + miniDP to DVi converter - require 2 x pin power connector - full retail pack
R3535 Gigabyte GV-R797oC-3GD - PCi-E 3.0 , with WindForce3x - 3 fans design with Triangle Cool , Ultra Durable ( with Low RDS(on) MOSFET + Low Power Loss - Ferrite Core Choke All-Solid Capacitor ) , gold plated HDMi connector , 28nm , DirectX 11 , crossfire-X , 3Gb 384bit 4 channel DDR5 , 32RoPs , 264Gb/sec memory transfer ; 3.79TFLoPS , 2048 ALU/stream processors ( pixel shader engine + vertex pipelines ) , 128 texture unit , core/memory : 1000/5500mhz , HDMI+DVi+2x mini DisplayPort , with HDMi to DVI + miniDP to DVi converter - require 2 x pin power connector - full retail pack

Sapphire GFX –

R4,299 Sapphire 21197-00-40G HD7970 - PCi-E 3.0 , dual bios , 28nm , 3Gb 384bit 4 channel DDR5 , 32RoPs , 264Gb/sec memory transfer ; 3790 GigaFLoPs, 118GT/s texture fill rate. , 2048 stream processors , 128 texture unit , core/memory : 925/5500mhz , HDMI+DVi+2x mini DisplayPort , HDTV+HDMi tv-out - require 2 x pin power connector , support HDMi 1.4a + Displayport 1.2 with MST , support 6x daisy-chian display via MST hub , support Eyefinity + DirectX 11 , crossfire-X , built-in HDMi codec+7.1 audio , 1080p HDCP Compliant - full retail pack
R4,399 Sapphire 21197-00-40G HD7970 OC edition with dual fan- PCi-E 3.0 , dual bios , 28nm , 3Gb 384bit 4 channel DDR5 , 32RoPs , 264Gb/sec memory transfer ; 3790 GigaFLoPs, 118GT/s texture fill rate , 2048 stream processors , 128 texture unit , core/memory : 1000/5800mhz , HDMI+DVi+2x mini DisplayPort , HDTV+HDMi tv-out - require 2 x pin power connector , support HDMi 1.4a + Displayport 1.2 with MST , support 6x daisy-chian display via MST hub , support Eyefinity + DirectX 11 , crossfire-X , built-in HDMi codec+7.1 audio , 1080p HDCP Compliant - full retail pack

R4,999 Sapphire 11197-12-40G HD7970 Vapor-X edition with dual fan- PCi-E 3.0 , dual bios , 28nm , 3Gb 384bit 4 channel DDR5 , 32RoPs , 264Gb/sec memory transfer ; 3790 GigaFLoPs, 118GT/s texture fill rate , 2048 stream processors , 128 texture unit , core/memory : 1050/6000mhz , HDMI+2xDVi+DisplayPort - require 2 x pin power connector , support HDMi 1.4a + Displayport 1.2 with MST , support 6x daisy-chian display via MST hub , support Eyefinity + DirectX 11 , crossfire-X , built-in HDMi codec+7.1 audio , 1080p HDCP Compliant - full retail pack

R6,199 Sapphire 11197-05-40G HD7970 Vapor-X OC edition with dual fan- PCi-E 3.0 , dual bios , 28nm , 3Gb 384bit 4 channel DDR5 , 32RoPs , 264Gb/sec memory transfer ; 3790 GigaFLoPs, 118GT/s texture fill rate , 2048 stream processors , 128 texture unit , core/memory : 1100/6000mhz , HDMI+ 2xDVi+2x mini DisplayPort - require 2 x pin power connector , support HDMi 1.4a + Displayport 1.2 with MST , support 6x daisy-chian display via MST hub , support Eyefinity + DirectX 11 , crossfire-X , built-in HDMi codec+7.1 audio , 1080p HDCP Compliant - full retail pack

Asus GFX –

R4,499 Asus HD7970-3GD5 - PCi-E 3.0 , dual bios , 28nm , DirectX 11 , crossfire-X , 3Gb 384bit 4 channel DDR5 , 32RoPs , 264Gb/sec memory transfer ; 3.79TFLoPS , 2048 ALU/stream processors ( pixel shader engine + vertex pipelines ) , 128 texture unit , core/memory : 925/5500mhz , HDMI+DVi+2x mini DisplayPort , with HDMi to DVI + miniDP to DVi converter - require 2 x pin power connector - full retail pack

R4,599 Asus HD7970-DC2-3GD5 DirectCu ii edition with dual fan + super alloy capacitor - PCi-E 3.0 , dual bios , 28nm , DirectX 11 , crossfire-X , 3Gb 384bit 4 channel DDR5 , 32RoPs , 264Gb/sec memory transfer ; 3.79TFLoPS , 2048 ALU/stream processors ( pixel shader engine + vertex pipelines ) , 128 texture unit , core/memory : 925/5500mhz , 2xDVi+ 4x DisplayPort , with DVi to HDMi converter - require 2 x pin power connector - full retail pack

R4,799 Asus HD7970-DC2T-3GD5 DirectCu ii Top edition with dual fan + super alloy capacitor - PCi-E 3.0 , dual bios , 28nm , DirectX 11 , crossfire-X , 3Gb 384bit 4 channel DDR5 , 32RoPs , 264Gb/sec memory transfer ; 3.79TFLoPS , 2048 ALU/stream processors ( pixel shader engine + vertex pipelines ) , 128 texture unit , core/memory : 1000/5600mhz , 2xDVi+ 4x DisplayPort , with DVi to HDMi converter - require 2 x pin power connector - full retail pack

Thanks again for all your help and time!