Need Help with new non-gaming system

This build comes in at just below your budget and will get your brother the light gaming and everyday workflow he needs. This will run most light games such as WoW or LoL or SimCity with no problems.
Seeing as you already have a case, PSU, and HDD I have made those appear as already purchased. I didn't see your case on partpicker so I didn't add that in but everything should fit just fine. You may need to update the bios on this build before you can properly use the CPU.
(I am also assuming you have a monitor, mouse and keyboard as well)

adjusting for the fact that you still need a PSU and an HDD here is a redesigned list for you.
It comes in at about $345 before rebates and discounts.

PCPartPicker part list / Price breakdown by merchant

CPU: AMD FX-6300 3.5GHz 6-Core Processor ($98.89 @ OutletPC)
Motherboard: Gigabyte GA-78LMT-USB3 Micro ATX AM3+ Motherboard ($50.98 @ Newegg)
Memory: Crucial Ballistix Sport XT 8GB (2 x 4GB) DDR3-1600 Memory ($34.99 @ Amazon)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive ($46.89 @ OutletPC)
Video Card: MSI GeForce GT 730 2GB Video Card ($65.99 @ SuperBiiz)
Power Supply: EVGA 430W 80+ Certified ATX Power Supply ($16.98 @ Newegg)
Total: $314.72
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2016-02-17 01:03 EST-0500

This build comes in at just below your budget and will get your brother the light gaming and everyday workflow he needs. This will run most light games such as WoW or LoL or SimCity with no problems.
Seeing as you already have a case, PSU, and HDD I have made those appear as already purchased. I didn't see your case on partpicker so I didn't add that in but everything should fit just fine. You may need to update the bios on this build before you can properly use the CPU.
(I am also assuming you have a monitor, mouse and keyboard as well)
To view the build with more details click on the blue words titled "PCPartPicker part list"

PCPartPicker part list / Price breakdown by merchant

CPU: Intel Core i5-4460 3.2GHz Quad-Core Processor ($174.89 @ OutletPC)
Motherboard: MSI H81M-P33 Micro ATX LGA1150 Motherboard ($44.89 @ OutletPC)
Memory: Crucial Ballistix Sport XT 8GB (2 x 4GB) DDR3-1600 Memory ($34.99 @ Amazon)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive (Purchased For $0.00)
Video Card: MSI GeForce GT 730 2GB Video Card ($65.99 @ SuperBiiz)
Power Supply: EVGA 430W 80+ Certified ATX Power Supply (Purchased For $0.00)
Total: $320.76
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2016-02-17 00:25 EST-0500

in your case you only need it for light gaming and as a result the AMD CPU is more than capable. Now if you were looking to run the latest AAA titles at high graphic settings in 1080p with solid FPS you would go with a much better Intel CPU and a way beefier GPU. But this will do more than a good enough job for the day to day work tasks and school stuff with light gaming. So in your case Intel VS AMD isn't relevant. If you upped your budget to about $650 you could get a great entry level gaming rig that will run the latest games at decent settings with solid FPS. If you were interested in such a build you can see it in this list below. Otherwise in response to what you were looking for in your original post that AMD rig is more than capable.


PCPartPicker part list / Price breakdown by merchant

CPU: Intel Core i5-4460 3.2GHz Quad-Core Processor ($174.89 @ OutletPC)
CPU Cooler: CRYORIG H7 49.0 CFM CPU Cooler ($34.50 @ Newegg)
Motherboard: Gigabyte GA-Z97-HD3 ATX LGA1150 Motherboard ($90.88 @ OutletPC)
Memory: Crucial Ballistix Sport XT 8GB (2 x 4GB) DDR3-1600 Memory ($34.99 @ Amazon)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive ($46.89 @ OutletPC)
Video Card: EVGA GeForce GTX 950 2GB FTW ACX 2.0 Video Card ($172.88 @ OutletPC)
Power Supply: Corsair CX 500W 80+ Bronze Certified Semi-Modular ATX Power Supply ($42.98 @ Newegg)
Total: $598.01
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2016-02-17 01:41 EST-0500

you could take the gpu off the build if you wanted to.
yes the i5 is better.
as for operation having an i5 over the amd or an i3 will be faster overall.
in regards to your question about i3 vs i5 think about it this way:

each core runs at a voltage of so many GHz (determining how much information can be pushed through it and processed at any given time) and a newer cpu with a slightly lower GHz than a older one doesn't necessarily mean it's slower per core because newer architecture comes into play as to how well optimized said cpu is when running per core. now each core can be seen as a single thread and a single thread processes a set amount of information. if you have a cpu with 2 cores then you have 2 cores simultaneously processing a set amount of information per core. now lets say for example that each core handles a max amount of information valued at 10 and processes that information within 1min. with a dual core cpu it will handle processing a max amount of information at a value of 20 every minute. now lets say you have your computer processing an amount of information at a value of 120. the dual core will process all of this information in a total of 6 minutes. but with a quad core which has 4 total cores it will process this information in a total 3 minutes. however, the speed of the core which is measured in GHz can also determine how much data a single core can process and how much it can process at maximum and with newer architecture than the dual core the quad core will process more per core at any given time and essentially faster even though it runs each core at a lesser amount of GHz than the dual because of the newer architecture that allows the cpu to do more with less.

And that is basically CPU 101 for dummies.
I hope this helped you to understand more of how computers work and helps you to make appropriate choices in the future when building another PC. But don't be afraid to ask for help at places like TomsHardware because we here are always happy to help a noob become a master as we were all noobs once and it was others that helped us become masters so naturally we pay it forward.

But on a side note, having a dedicated GPU can help in more than just gaming. It is also used for video editing and media processing as well as any other graphically intensive operation.

On the topic of heavy video processing you would want hyper threading. But hyper threading is a much longer topic to explain. the gist of it is that with a hyper threaded cpu each core runs like two cores because each physical core runs as two logical (virtual) cores. Why this is and how it does this and the performance gain with pros and cons is the long part. Hyper threading is only found in i7 cpu's and the AMD FX (and some other select AMD cpu's as well) line of cpu's. If you wanted more info on that and what it's good for and why you can PM me and we can talk about it some more.

I'm not sure if everything is 100% compatible as I don't know what case you've decided to go with but going off of just the parts themselves things look good.

However I've made a couple of changes and you can see them below. The main one is the HDD since the barracuda will perform the same if not better than the Hitachi but for nearly half the price.

I've take your choice of G.Skill Ripjaws RAM and chosen the X series which is much better. As for the CAS timings normally lower is better but once you get to 8 and 9 you will not see any significant difference (if you were to run benchmark tests there would be a difference in scores but it wouldn't be enough to be a relevant thing)

Not sure about your choice of PSU since I've never seen anyone use that specific EVGA model but it looks to be alright. I would prefer a semi or full modular PSU but the choice is yours in the end. The difference between non/semi/full modular is how manageable the cables are and whether or not they come sleeved or exposed.

As for the MSI GPU I didn't know which version of the 2GB model you have or went with as a choice so I just placed the better one of the choices in the list.

Since you've said something about the front panel usb and audio headers I assume you have a case and that it has those on it so I've chosen the asrock mobo (yet again though I can't confirm 100% the compatibility of everything since I don't know what case you are using)

one last thing. I have overridden the pricing choices on a few of the items. I've gone with B&H for some, Newegg for others and Amazon for one of them. The B&H choices are no tax with free shipping so it's the best price option. The newegg choices are there since they are the only option with the best price and the amazon choice is there becuase it's cheaper after taxes and has free shipping. You of course can choose to buy from newegg 100% if you are the kinda person to do mail in rebates but be warned. the price in the PCPP list isn't 100% accurate as it doesn't account for taxes on anything. to get a full estimate of how you would spend on items you should add them all to your cart and get to near full checkout to see the final price after taxes and shipping on items that would have them.

So without further ado I give you the slightly modified list based on your given selections in your previous statement.
P.S. - there are some mail in rebates on the newegg ones so to see closer to the full price just follow the link to the pcpp list to see more details.

PCPartPicker part list / Price breakdown by merchant

CPU: Intel Core i5-4460 3.2GHz Quad-Core Processor ($181.83 @ B&H)
Motherboard: ASRock H97M PRO4 Micro ATX LGA1150 Motherboard ($62.98 @ Newegg)
Memory: G.Skill Ripjaws X Series 8GB (2 x 4GB) DDR3-1600 Memory ($32.99 @ Newegg)
Storage: Seagate Barracuda 2TB 3.5" 7200RPM Internal Hard Drive ($71.99 @ B&H)
Video Card: MSI GeForce GT 730 2GB Video Card ($71.99 @ B&H)
Power Supply: EVGA 430W 80+ Certified ATX Power Supply ($34.72 @ Amazon)
Total: $456.50
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2016-02-27 17:19 EST-0500

2133 is standard for dd4, 2400 is the next step up., ad most mobos cam handle up to 3000 or faster

slight improvement...mostly in benchmarks. go with what is cost efficient

H97 is for haswell, its skylake equivalent is H170.
H110 is a bargain motherboard for skylake, with a slower pcie bus and fewer usb and sata ports