Question 1

What is hashrate for scrypt? If using two, will hash rate scale linearly? (ie: double for two?)

Accepted Answer

These 7990's can achieve in the 1500kh/s rate for the two gpu's combined, or 3000kh/s for a pair.  scaling is pretty much linear, you're not crossfiring these they are just running as a secondary installed card.

Question 2

hi. i purchased this card for the purpose of mining i am just wondering.. i ran this card for about 15 mins and temps got up to 80 degrees on both of the cards.. now i am wondering. is it safe to be running the card on gpu usage 100% with those temps for more than an hour or even 12+ to say the least? i know it might damage the cards long term if it goes over 90 degrees? also, i noticed an odd smell coming from the card once i starting using it after 15 mins of mining. wondering if that is normal? smell like brand new product/ maybe plastic or wire.. i put this card inside my gaming computer which is an alienware aurora r4 with 875w.. everything works normally but will the motherboard get damaged somehow if it runs this hot? maybe it's because i  had the fans running at 100% to keep it cool? let me know that as well thanks!

Accepted Answer

95 degrees celsius is the limit on the card,  would keep the fans on 100%.  I noticed the card was pretty hot and I got a spot cooler for this card and would recommend either that or a side case fan...in addition this card can be undervolted as atleast the chips that came on my board had a pretty decent ASIC quality of 70.5% on one chip and 76% on the other.  I have undervolted both the chips to 1.1 volts down from the 1.2 stock voltage and saw temperature drop in the range of 8 degrees celsius.  I used Sapphire Trixx software to undervolt the card and also the cards are pretty decent overclockers as I was able to get 1060 and 1085 on each core respectively upping my hash rate to 1490 Khash.  You may also want to get something like a Vantec Spectrum card cooler although it is really only effective at getting one of the cores to drop temps.  Its a really great card once you start playing with the voltages especially since these cards are unlocked in that regard.

Question 3

What type of Motherboard this one can be Compatible with?

Accepted Answer

Any motherboard with a PCI-Express x16 slot will accept this card.  However note that it takes up three slots, and also has significant power requirements (minimum power supply recommended is 750W for 1 card or 1000W for 2 cards.  Less if you have very efficient power supplies but play it safe).

Brand	XFX
Model	FX-799A-6NF9

Chipset Manufacturer	AMD
GPU Series	AMD Radeon HD 7000 Series
GPU	Radeon HD 7990
Core Clock	950 MHz
Boost Clock	1000 MHz

Effective Memory Clock	6000 MHz
Memory Size	6GB
Memory Interface	384-Bit x2
Memory Type	GDDR5

DirectX	DirectX 11
OpenGL	OpenGL 4.2

DisplayPort	4 x Mini DisplayPort 1.2
DVI	1 x DL-DVI-I

XFX Radeon HD 7990 6GB GDDR5 PCI Express 3.0 x16 CrossFireX Support Graphics Card FX-799A-6NF9

Learn more about the XFX FX-799A-6NF9

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Warranty & Returns

Warranty, Returns, And Additional Information

Warranty

Return Policies

Manufacturer Contact Info

Eyefinity Support	Yes
CrossFireX Support	Yes
Cooler	With Fan
Power Connector	2 x 8-Pin
Dual-Link DVI Supported	Yes
HDCP Ready	Yes

Form Factor & Dimensions
Card Dimensions (L x H)	12.20" x 4.41"
Slot Width	3 Slots

Item#: N82E16814150694