Recommendations for PC -- for modest system --

Looking for recommendations for PC for a modest AV system -- I know all things audio are personal preference - but still want feedback on experiences with PCs under the the <$400ish mark - 

My meager system:

Marantz 7705
ATI 7ch x 200 amp
B&W CDM9NT x4 plus matching center

Budget - is low compared to many here - but still looking for some solid guidance - <$400 for each PC for amp and AVP. If I can spend less - that is ideal - Not looking to squeeze every last bit of sweetness from my AV system - just want something that is a balance between - far better than stock PCs -- and improves system overall - on the exponential curve of price vs performance.

Considering the following: 

Audioquest - one primary reason I am considering AQ - I can purchase at 45% msrp...
Madscientist - unfamiliar but seem a few here have exp with them... 
DIY?  -- Can I approach equal or better quality - for less if I DIY with the likes of with neo or dh cable or other with WG or other connectors... Is it worth the effort to DIY at budget I have set? 
Synergistic Research - considering - but I see none in the <$500 range... 

Thanks in advance.

DIY? -- Can I approach equal or better quality - for less if I DIY with the likes of with neo or dh cable or other with WG or other connectors... Is it worth the effort to DIY at budget I have set?

No. Not even close. I know one guy with 30 years building DIY cables trying all the hot schemes who every time he showed me one I had something in my used cable drawer that we BOTH agreed sounded better and cost less than he spent on parts. Waste. Of. Time.

Synergistic Research - considering - but I see none in the <$500 range...

A used SR Master Coupler is under $400 and a darn fine power cord. A used Blue can usually be found for $500 or less. Synergistic is so consistent quality wise you can be safe going with any model in your price range, and generally the newer the better. If you find one with Active Shielding those are a great choice because they'll sound good stock and can be upgraded with better caps and diodes in the wall wart by Michael Stallone for a huge increase in performance for something like $50-75. 
I just built a PC with DH Labs Red Wave bulk cable and Furutech FI-28 (R)/FI-28M (R) rhodium connectors and it is really good. Five ft cable and Furutech connecters for about $400 in parts. You can use generic rhodium AC connectors from Parts Connexion which cost much, much less than the Furutechs. The Red Wave was $800, and is now available for $560 assembled from factory but comes with less resolving Wattgate connectors than listed above, so you can really save some money building yourself.

Another home brew cord I am high on is the Nanotec bulk cable which you can purchase from MCRU in the UK for about the same price as the Red Wave. Use either the Furutech or Parts Connection rhodium connectors and for $300 to $400 you get an a $800 cable.
The Nanotec is a little smoother than the Red Wave, but perhaps a bit less revealing. Both are excellent.

Other good cords I have tried:

Black Shadow with Rhodium connectors often available on Audiogon for under $200 is a real steal.

The IsoTek EVO3 Premier AC power cable is another good performing cable for the money, but pretty lit up if that is your cup if tea.

I am using a Shunyata Venom HC power cable on my Shuyata power strip that supplies everything but my amp and sub and it is pretty good but had an ungodly long breakin period. Its available in 15A and 20A versions fir $295.

I have not listened to AQ’s newer cables, but I hear good things about them. I am running some of their older PCs on my sub and in an office system. If you can get that kind of pricing you should look seriously. You could score a Blizzard or Thunder PC for under $400.

I would not hesitate to call the good folks at the cable company and get their opinions.
Cullen and Audio Envy would be my budget choices, and I believe you can return them if they don’t provide a significant upgrade to stock.  Best of luck. 
Unless you're having a specific problem, I'd save your money and use stock PCs in that system. Your money is best used to upgrade your existing components, imo.
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Music Direct has a sale on Shunyata - Venom HC v2 Power Pak Cable Bundle. You can purchase a 3-pack for $595 or a 5-pack for $875.
These usually go for $400/ea. You may have to wait a bit as they are out-of-stock.
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Thanks for all the input.

Other than the concept of dedicated power for 20A line just for AV gear... what will it get me in real world performance?  

I understand one line - no shared power is better - but - if everything else is 'off' on the that shared line... would it not be the same as having a dedicated line?


Why is DIY not a good option if I am using essentially what other DIY houses are using? Why wouldn't results be comparable? 

I will check out audio envy as an option...
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Try Pangea. It is a budget PC from Audio Advisor. They are in my system and I feel they are worth the investment.
If you haven't already, call GIK Acoustics to get advise on improvements using acoustic panels. You may get better sound for the same cost.
HDMI cables:  cable between PC and Marantz AV7705.  First, you really want a very good video card.  The power supply and circuits on the video card actually influence the audio/video quality (like GeForce 1050 or better).  Small cheap video cards are okay, but not as good for video quality.

Probably one of the best HDMI cables I have found for the money is the older Wire World Starlight 5-2 (yes, 10+ years old) or a Starlight 6.  Make sure you get at least 2 meters (not too short).  You can find these used on ebay (anwhere from $150 to $400).  These older generation cables used a single 24awg silver-plated copper solid core conductor.  I found they provide excellent audio/video and beat out a lot of other cables.  DO NOT get the "Silver Starlight 6" or anything newer.  The newer Wire World generations use dual 2x26awg conductors and they just do not perform as well (audio not as good, video slightly washed out).  Not sure what is causing this, but I suspect it's dual/multiple conductors sending high speed pulses and having timing error between them.

If you want a new cable, the cryo-treated Neotech NEHH-4200 from Audio Sensibility is excellent for the money (not as good as the WireWorld above).  This is a 26awg silver-plated OFC copper conductor design.  Audio Sensibility is a Canadian company and it's around $78 US (plus shipping).

I tested Audioquest HDMI cables and was not impressed at all.  I auditioned a Vodka HDMI and video was okay, but audio was thin and bright.  I found out that they use very small 30awg conductors.

I would avoid Pangea because it's gold-plated plugs and the copper isn't top shelf.  Look for a used Audioquest NRG-2 or NRG-4 cable and chop the ends, then put on Furutech Rhodium connectors.  You can look at other cable (Kimber PM14 for example).
Why is DIY not a good option if I am using essentially what other DIY houses are using? Why wouldn't results be comparable?

millercarbon seems to be completely against DIY and has consistently pushed Synergistic Research as a solution for any problem.  One man's opinion.  I have been doing DIY cables for 10+ years and some of my cables have beat out other more expensive manufactured cables.
Cullen, Audio Envy, Audio Sensibility, all very good.  Move up to Inakustik if you want something really good, but it might be out of your budget.
DIY is a great option, particularly if you are on a budget and not looking for anything really esoteric. Wire/cable companies generally don't offer their very best cable for bulk purchases, but there are great options that are equivalent to finished cables costing $500 to $1500. 

The DH Labs Red Wave cable that @knownothing  mentioned is a good example. This cable sells bulk for $40/ft or less (I think Parts Connexion has this on sale for $30/ft right now). Couple with higher-end connectors from WattGate or Furutech, and add some TechFlex (optional) and you have a PC that will cost you $300 to $400 (not including your time) that would cost you twice that as a finished product and is an excellent PC.

If your budget is lower, using DH Labs Power Plus with lower cost WattGate (or Viborg or HifiKing if you want to spend even less) will get you a power cord that is way better than stock cables for about $100. 
Having very good results with the Silnote Audio GL Reference power cables, easily has beaten out some offerings from some of the more well known brands in my system.Silnote advertised here on Agon and their prices are right for a very well made cable, $99.00 for a 3 ft. run. Cullen cable is another I have had very positive results with. Enjoy the music
Furutech,Oyaide, Neotech, IEGO have nice proposition in your budget.
I would go with Furutech plugs as having the most firm contact.
Consider 14AWG for Marantz and 10AWG for ATI.
Core Power Cables $299.00 or less for 2 at Underwood Hi Fi very good cord cheap.
Any 12 gauge copper (not copper clad) ordinary multi strand power cable sold at Home Depot would do and would not cost you more than 20 bucks.  

Everything else is snake oil.

Cullen, Audio Sensibility and Audio Envy are all great internet direct companies with good customer service.  In my current setup the Audio Envy power cables are doing a great job. His prices are well under your limit and he has a trial period. I have also owned PC's from the other two companies and they are in use in other systems around the house.
I followed advice from this forum and purchased a Synergistic Research Master Coupler X2 in 20A for my amplifier. Well I can tell you I am so glad I bought it, there is a difference with it in my system.
Oh, I purchased it used for about $500 from memory, + shipping.

I have been interested in the Mad Scientist - Nitro NANO Power Cord and I've been on Facebook with the manufacturer (I think the 10% discount is still current?). I have been using Mad Scientist - Heretical Digital Cable with KLE Silver Harmony Plugs, with favorable results. However a review of his USB still placed Curious Cables USB as better. (I used to build Curious Cables, solid annealed pure silver data wires in USB), so I'm still doing my due diligence.

The Inakoustik power cords and power conditioning certainly has my attention, and I am looking into them as well.

Keep an eye out for the Master Coupler used, if you don't for whatever reason like it, it'll hold it's value well. For me, I'm going the upgrade mentioned with Michael Stallone, and my MC X2, it's a dead set keeper!
You'll only need 15A with that 7705 or virtually any SS AB or D amp. Not sure you'll hear any diff with an a/v rig.
Of course the bigger gauge wire to the outlet the better.
Good luck turning everything off.
You'll probably need a flashlight during the best SQ time portal.
You can buy AQ Monsoon Extreme 1M for $301.50 or 2M for $355.50.
These are Garth Powell engineered with silver on copper contacts.  They are one step below the level where the battery packs come in.  At your discount I don't see how anything will beat these, but I'm not basing on any listening tests, just the bare economics and the sterling rep AQ has for their newer power products...
@lightfighter2018 - everything off is good, but who wants to fumble around in the dark?

If you have the option to install a dedicated line from your breaker box, that is a good idea. 20A breaker. I would use 10AWG supply line too while you are at it. And at least hospital quality outlet(s) or better.

What if anything are you using for a power strip or conditioner? If needed, this is where your AudioQuest discount could yield great value.

Everything matters. Dollars spent upstream reap greater rewards (and shine a light on wrong turns) for all upgrades downstream.
 "Everything matters.    Dollars spent upstream reap greater rewards (and shine a light on wrong turns) for all upgrades downstream."       +1       Also; anything from Synergistic Research or Kimber, will serve you well.