Can someone tell me a good graphics card compatible with my pc specs?

Solution
And your budget for the graphics card? There are cards over $500 and lower than $200 it really matter how much you want to spend.

Also what resolution will you be playing at and what games do you want to play at what graphic config?

AMD FX-8310 3.4 GHz
Processor Main Features
64 bit 8-Core Processor
Cache Per Processor
8 MB L3 Cache
Memory
8 GB DDR3 1600
Storage
2 TB SATA 7200 RPM
Optical Drive
SuperMulti DVD RW
Graphics
AMD Radeon R7 240 2 GB
Ethernet
Gigabit Ethernet
Power Supply
300W
Operating System
Windows 8.1 64-Bit

CPU
CPU Type
FX-8000 Series
CPU Speed
FX-8310 (3.40 GHz)
L3 Cache Per CPU
8 MB
CPU Main Features
64 bit 8-Core Processor

Graphics
GPU/VGA Type
AMD Radeon R7 240 2 GB

Memory
Memory Capacity
8 GB DDR3
Memory Speed
DDR3 1600
Memory Slot (Total)
2

Hard Drive
HDD
2 TB
HDD Interface
SATA
HDD RPM
7200rpm
HDD Spec
Free 100 GB Webstorage for 1 year

Optical Drive
Optical Drive Type
DVD Super Multi

Display
Screen Size
1.6"

Communications
LAN Speed
10/100/1000Mbps
WLAN
802.11ac Wireless LAN
Bluetooth
Bluetooth 4.0

Front Panel Ports
Front USB
2 x USB 3.0
Front Audio Ports
2
Card Reader
6-in-1: SD / SDHC / MS / MS Pro / XD / MMC

Back Panel Ports
PS/2
1 x PS/2 (Keyboard/Mouse)
Video Ports
1 VGA, 1 DVI, 1 HDMI
Rear USB
2 x USB 3.0
4 x USB 2.0
RJ45
1 port

Expansion
PCI Slots (Available/Total)
2 PCI-e X1
1 PCI-e X4
1 PCI-e X16

Mouse
Mouse Type
USB Mouse

Keyboard
Keyboard Type
USB Keyboard

Dimensions & Weight
Dimensions (H x W x D)
16.00" x 6.90" x 14.90"
Weight
18.27 lbs.

 
And your budget for the graphics card? There are cards over $500 and lower than $200 it really matter how much you want to spend.

Also what resolution will you be playing at and what games do you want to play at what graphic config?
 
Solution
+FrostinFire Am I correct in assuming that you have a Asus M32BC-B01 ? Regardless, since you only have a 300 watt OEM power supply, you barely have any options. The only option that'll work with that power supply is a GTX 750 Ti. I'm honestly not sure how much more graphically powerful that is than your current R7 240, but a wild guess is 40% - 60% more powerful. Sounds like a lot, but it's not what I would do. FYI, I believe the Intel counterpart to your machine came with a 350 watt PSU.

What I would do:

buy a replacement power supply.
buy a GTX 1060 (releasing soon).
sell R7 240.
toss OEM 300 power supply.

Below are a few videos that you should watch. First one is guy with an upgrade power supply installing a GTX 970. The GTX 1060 is "rumored" to meet or exceed the performance of a GTX 980. The second video simply shows the inside of the Intel variant. If you do indeed opt to upgrade the power supply and graphics card, you'll need to be aware of how much space you have to work with inside the case, as it's dimensions look tight.

Zotac Gtx 970 Install ASUS m32
https://www.youtube.com/watch?v=g7myJ9LkGAo

Asus M32 Review
https://www.youtube.com/watch?v=AnixIFmHmZs

specs:
AMD FX-8310
8 GB DDR3 (1600)
2TB SATA 7200 HDD
AMD Radeon R7 240 2GB
Power supply 300Watt
windows 8.1 64 bit

https://www.asus.com/us/Tower-PCs/M32BC/specifications/

Conclusion: Upgrading to just a 750 Ti, is what I would personally consider to be a waste of time and money. Were it me, I'd go for the GTX 1060. The other competing option is the AMD RX 480; both of which require a power supply upgrade.
 
Ah, my bad, missed that power supply. Anyways your pc can even handle a GTX 1080 easily. It just comes down to how much you want to spend. But without a doubt, it is essential that your replace your power supply with a high quaility one. What is your budget?
 
PCPartPicker part list / Price breakdown by merchant

CPU: Intel Core i3-6100 3.7GHz Dual-Core Processor ($110.99 @ SuperBiiz)
Motherboard: Asus Z170-A ATX LGA1151 Motherboard ($150.99 @ SuperBiiz)
Memory: G.Skill Ripjaws V Series 16GB (2 x 8GB) DDR4-3000 Memory ($69.99 @ Newegg)
Total: $331.97
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2016-07-10 03:49 EDT-0400

I would get this now, and later on (maybe 1-4) years you can upgrade to a i5 6600k or i7 6700k and get a nice Noctou D15 cooler.
 




 




 
First of all you can forget about the Corsair CX Series.. They are no good.. Again, check the PSU Tier List. but for that price range I would say like a XFX TS 650w. but It's non Modular. take some time to check the list and read some reviews on the models/price range that your interested in.
 


Already read some reviews about this one
EVGA SuperNOVA 650 P2
 


Ok thanks for your help but if i upgrade my PC with that PSU i will be able to upgrade my pc toma gtx 1060 right?
 
+FrostinFire I'm reasonable sure that an EVGA P2 650/750/850 will fit in your case based on the video I hyperlinked earlier. The guy successfully installed the Zotac GTX 970 along with a ThermalTake Smart M850W PSU, which has dimensions of 3.34"(H) x 6.30"(L) x 5.91" (W). The EVGA P2 650 has two of the same dimensions, with only the length being 0.20" longer for a total of 6.50".

Thoughts: The EVGA P2 line is one of my favorites and I personally own several of the EVGA P2 850 PSUs. They are fantastic: EVGA customer support, manufactured by SuperFlower, tier 1 on Tom's Hardware PSU tier list, 10 year warranty, fully modular and platinum efficiency. With that said, it's expensive IF you only plan to upgrade this particular computer and never see yourself upgrading beyond a GTX 1080. If that fits your scenario then a SeaSonic S12II 520 will handles your needs ( http://www.newegg.com/Product/Product.aspx?Item=N82E16817151094&cm_re=SeaSonic_S12II_520-_-17-151-094-_-Product ). However, if you plan on keeping your new power supply beyond the life of this computer, and can see yourself one day upgrading to a GTX 1080 Ti (titanium level successor to the 980 Ti that hasn't been officially announced yet) then the EVGA P2 650 would be a great way to go. I'd even go as far to say that you might consider the P2 850, as it's currently only $10 more on NewEgg, and would give you the future upgrade option of two GTX 1080 Ti's in SLI, if you ever built a new machine; your current one only has a single PCIe x16 slot. For only $10 more, "in for a penny, in for a pound" comes to mind.

EVGA P2 850
$109.99 after $20.00 rebate
http://www.newegg.com/Product/Product.aspx?item=N82E16817438056

SeaSonic S12II 520
$64.99
http://www.newegg.com/Product/Product.aspx?Item=N82E16817151094&cm_re=SeaSonic_S12II_520-_-17-151-094-_-Product

Btw, I retract my earlier suggestion that you toss the OEM 300 watt power supply after you swap it out. You might want to hold onto it for the future when you're ready to step-up to a new computer. You'd have the option of transferring the EVGA (or whichever) PSU to a new build and then you could re-install the OEM 300 watt unit and sell the machine to someone on Craigslist or Ebay.

*** power requirements for graphics cards ***
http://www.realhardtechx.com/index_archivos/Page362.htm
 

Ohhh thank you im gonna buy the EVGA 850 W and loook for a good graphics card
But do you think the EVGA 850 W will fit on my Pc?
btw thanks for the help