Trying to improve gaming performance on my sons computer.
I am also helping my sister in law purchase a gaming computer for her son.

My line of thought is two fold.

First: when it comes to computers or phones or whatever. Without working knowledge. We pay for a lot of crap we don't need, or use. And we (I) often overlook the items that MAKE a real difference.

Second: The extreme high end. Or even outside my budget where cash becomes painful. Is futile in electronics because most things will be either outdated or under-perform when compared to newer releases within two to three years. As far as I can tell. A computer is one of the worst "investments" a person makes. Right behind purchasing a new car.

My (possibly flawed) understanding of compromise and balance in regard to gaming computers. In order of their priority in regard to gaming.

Monitor
Graphics card
Ram
Processor

It is also my understanding that any result with be limited to the capabilities of the least performing component??? I think a better graphics card would do the trick for me. But I'm not sure. And I dont WANT to spend money on something that is not fully utilized. That's why am ASKING you all for your help.

Once that question (priority) is answered I will share the specs of both the current computer and monitor.

My goal for my boys upgrade is, to not overpurchase and achieve the best balance for GAMING within my budget. Like to keep the budget range between $250 and $350.

My goal to help my sister in law. To find an ALREADY balanced complete GAMING system (turn key) below $700

Both are desktops

Thanks in advance for your help an patience.
I will follow this by posting my existing specs.Sons computer. The one I would like to upgrade.

Moniter specs:


Acer
Model
S275HL bmii (UM.HS5AA.001)
Cabinet Color
Black

Display
Screen Size
27"
LED Backlight
Yes
Widescreen
Yes
Recommended Resolution
1920 x 1080
Refresh Rate
60Hz
Viewing Angle
178° (H) / 178° (V)
Pixel Pitch
0.3114mm
Display Colors
16.7 Million
Brightness
250 cd/m2
Contrast Ratio
ACM 100,000,000:1 (1000:1)
Response Time
6ms (GTG)
Panel
IPS

Connectivity
Input Video Compatibility
Analog RGB, Digital
Connectors
D-sub, HDMI
D-Sub
1
DVI
No
HDMI
2
DisplayPort
No

Power
Complies with
ENERGY STAR
Power Supply
100 - 240 VAC, 50/60Hz
Power Consumption
Energystar Off (typ.): 0.5W
Energystar Sleep (typ.): 0.5W
Energystar On (typ.): 36W

Computer specs:
HP ENVY h8-1540t
Operating System
Windows 8 Professional (64-bit)
DISPLAY
Monitor
No
Monitor Features
N/A
MOTHERBOARD
Chipset
Intel X79 Express
RAM
RAM Type
DDR3 SODIMM
RAM Capacity
10 GB
Preloaded Memory
DDR3-1333
PROCESSOR
Processor Model
Intel Core-i7 3820
Processor Type
Quad Core
Frequency
3.6 GHz
Cache
10.0 MB
HARD DRIVE
Interface
SATA
Memory Storage
2000 GB
RPM
7200
GRAPHICS
Video Card
GeForce GT 640
Sound Card
Integrated
COMMUNICATIONS
Wi-Fi
Yes (Type: 802.11b/g/n)
Bluetooth
No
Infrared
No
Card Reader
No
Modem
No
More Connections
PCI Express: 3
STURCTURE
Casing
Tower
Dimensions (WxHxD)
6.88 in x 16.22 in x 16.34 in
Color
Black
OTHER
Optical Drive
SuperMulti DVD Burner
Power Supply
460 W
Ports
15-in-1 multimedia card reader + Top I/O (2 USB 3.0 + 1 headphone jack + 1 microphone jack) + Front I/O (2 USB 2.0)
Camera
No
Microphone
Yes
Accessories
USB standard Keyboard, Mouse, TV TunerWith that system, your biggest limitation for gaming is definitely the graphics card, which one to go for will vary depending on your budget.

In order to get a higher end graphics card (Anything higher than a GeForce 750ti anyway) you will need to upgrade the power supply to a unit around 550w. It is important to not cheap out on this, cheap PSUs can be DOWNRIGHT dangerous!

In your budget you'd be looking at something like a NVIDIA GeForce 760 video card and a decent 550w PSU like this: http://www.newegg.com/Product/Product.aspx?Item=N82E16817207013&cm_re=xfx_550w-_-17-207-013-_-Product

The main thing to check is the size of the video card to ensure it will fit, you will need to look up the dimensions for the card you want to buy and then check those against the space in the case, the most important factor is usually the length of the card.

As far as the ordering for gaming, I would say that the ordering would be: Graphics Card, CPU, RAM and then Monitor. The monitor is nice to look at but it's much more important to have a PC that can actually run the game at a playable level than having a really nice monitor.