HalozyR

Oh this is a pre-built computer

I normally use:
 
OCCT, UserBenchMark, MSI Afterburner, HWInfo, and LatencyMon.
 
OCCT is a pretty flexible stress testing program that'll stress everything from your CPU to your power supply, and it'll record and monitor power usage, utilization, clockspeed, temperature, and much more so you can see what's happening while it's being stressed, and what happened if it failed. It isn't the best for full stability testing on a CPU or GPU, but if you do other tasks in the background to get a more dynamic load, it does well enough. It'll automatically stop if it detects CPU errors, and tell you if it detects GPU errors.
 
UserBenchMark is a fairly simple little program with a very nice website that gives you a rating for the relative performance of your hardware configuration compared to similarly tested configurations. It tests your entire system, and provides some useful information about how your changes have improved, or decreased your performance. It also stores logs on their website with a unique identifier for your computer so that you can see performance logs for the last few months. I like it because it's simple, quick, and it's got a nice interface. It's also fun to see what you can do to make your computer perform the best on the list. As far as grading components, they've pretty much already done all the work for you.
 
MSI Afterburner along with Rivatuner Statistics Server is an invaluable little program that will allow you to set up a custom fan profile for your GPU, as well as set up all sorts of statistical information in an on-screen display so that you can see what's happening with your hardware and utilization in real time while in games, or stress testing. This is important for diagnosing issues, as it gives you a clue as to what the computer is doing which can help to point you in the right direction when it comes to diagnosing problems, or improving the performance on your computer.
 
HWInfo is a pretty powerful tool, as well. It will basically give you all the sensor information on your computer that it has access to. For better or worse. Once you figure out what you're looking at, it gives incredibly in-depth information with regards to voltage, clockspeeds, and it will even show if there are any GPU or Hardware errors reported in Windows which is especially useful when it comes to overclocking. Too many times have I settled on an overclock after stress testing it for days, only to later down the line, run into an issue due to a slight instability. This program will allow you to see if your computer is having issues BEFORE it creates issues for you. Very, very useful.
 
Lastly, LatencyMon. You can technically get latency information through Windows performance monitor, but this is a much nicer GUI in my opinion. LatencyMon measures DPC, or the lantency created by defferred procedure calls. These calls occur when tasks must be delayed in order for more critical information to be managed. The problem with this is that nothing you really care about is considered critical, so quite often this will cause video and audio to skip and clip. This program will help narrow down the cause, and point you towards to problem driver or program. It's use in overclocking is helping ascertain system stability. As certain components of your computer become unstable, they may become unresponsive in which case, they will need to be restarted. This can introduce latency. This latency isn't always something perceptible, but noting huge spikes in latency after testing a seemingly stable overclock could indicate that it isn't as stable as you may think.
 
Oveclocking is fairly easy. Just know your limits, and play within them. Make sure that you fully understand the temperature and voltage limits for your components, and ensure that the sensors that you're using to determine these things are accurate. It's easy enough to just go out and pick up an IR temp gun for like $5-$10 to ensure that nothing is cooking. There are also many IR cameras that would functionally do the same. All in all, be smart, start slow. Learn from other people, read lots. All hardware will have it's quirks, and even different batches of the same hardware can be made with different components, so just be mindful and know what you're dealing with. Most importantly, have fun.
 
 
Good luck.

Credit to @Starelementpokeand @Energycore for helping out with this long-awaited refresh of the old PSU tier list by Aniallation (who previously went several months without logging in), leaving the old list in need of help. This is simply an update of the list that was flawed in creation by the PCMR subreddit and in dire need of a refresh.
 
This list is subject to change as new PSUs come out on a regular basis and standards may change or issues with units on the list may develop. A list of PSUs awaiting a tier on this list is at the bottom.
 
Tier 1 - Best
Aerocool - Project 7 Antec - High Current Pro, High Current Platinum be Quiet! - Dark Power Pro P10, Dark Power Pro 11, Straight Power 11 Bitfenix - Whisper Cooler Master - V-series (modular, not to be confused with the VSM), MasterWatt Maker Corsair - AX, AXi, HXi, RMi, RMx, SF, grey-label HX (2017), 2017 TXM greater than 650W Enermax - Platimax, Platimax Digifanless EVGA - G2, P2, PS, T2, 1000G1, 850W and above GS FSP - Aurum PT Gigabyte -  Aorus AP850GM LEPA - G1600 NZXT Hale90V2 Seasonic - X, Platinum, Snow Silent, all Fanless units, Prime (all series) Sentey - Platinum Power, Golden Steel Power Silverstone - Nightjar Super Flower - Leadex Gold/Platinum/Titanium, Leadex II Thermaltake - 1250D-T RGB, Toughpower Grand/RGB 1200W XFX - Pro Gold, Pro Black, XTS Tier 2
Antec - EDGE, TruePower Classic, EarthWatts Gold Pro Azza - Platinum be Quiet! - Pure Power 10 400W or greater Bitfenix - Formula Gold Cooler Master - VSM-series (semi-modular) Corsair - Most RM variants, HX (old), 550W/650W 2017 TXM, Vengeance Enermax - Digifanless, RG, GX EVGA - GQ, B2, 550W and 650W GS, GD, G3, G1+ (not to be confused with the G1) Fractal Design - Edison M, Tesla R2 650W/1000W, Newton R3 FSP - Hydro G, Dagger SFX Gigabyte - XP1200M Kolink - Continuum NZXT - Hale82 N higher-wattage versions Riotoro - Enigma Rosewill - Quark, Fortress, Capstone Seasonic - S12G, G-series/SSRM, M12II 750W/850W, Focus Plus Gold/Platinum, Focus Gold Sentey - Solid Power SS Silverstone - Strider Platinum Super Flower - Golden Green, Leadex Silver Thermaltake - Toughpower Grand/RGB, Toughpower Grand Platinum, Toughpower DPS Platinum XFX -  Pro XXX, XTR, TS Gold Tier 3
Antec - Neo ECO II be Quiet! - Straight Power E10 Bitfenix - Fury  Cooler Master - MasterWatt Corsair - 2017 "Grey unit" CXM***, CSM, some RM variants, 2017 CX - 450W CX have one PCIe connection Cougar - GX-S Deepcool - DQ-ST Enermax -  Enermax Revolution SFX 650W*** EVGA -  BQ 750W and up Fractal Design - Tesla R2, Integra M FSP - Hydro X, Aurum CM, Aurum Pro Lian Li - SFX-L LEPA - G600 NZXT - Hale82 N lower-wattage units OCZ - ZX PC Power & Cooling - Silencer Mk III, Turbo Cool Riotoro - Onyx Rosewill - Lightning, Silent Night, Tachyon, Photon Silverstone - Gold Evolution, Strider Gold, SX650/700/800 SFX, Strider Titanium Super Flower - Platinum King Thermaltake - DPS Gold/RGB, London, BlueEvo 2.0, Smart Pro RGB, Smart series >= 750W Vivo - 24K 650W XFX - Core > 650W, ProSeries Bronze >650W Zalman - EBT Tier 4
Antec - EarthWatts/EA Green, Earthwatts Platinum, High Current Gamer, Neo Eco  be Quiet! - Power Zone, Pure Power L9, Straight Power E9, Pure Power L8 Corsair - Old CXM "Green unit" variants, Rev. 3 "Green unit" variants, GS-series Cooler Master - GM, GX Storm, MWE Cougar - LX Enermax - Revolution X't EVGA - BQ under 750W, NEX Gold, B3 Fractal Design - Tesla R2 500W Inwin - Classic Series PowerSpec - PSX GFM Rosewill - Capstone G Seasonic - SS, SSP, S12II/M12II, ECO 430W Silverstone - Strider Plus, Gold SFX Thermaltake - Toughpower Gold, Paris XFX - TS Bronze Tier 5
Antec - Basiq VP-F, Basiq BP be Quiet! - Pure Power 10 under 400W. Corsair - Rev. 2 CX "Green unit" variants, VS "grey units" Enermax - NaXn 82+ EVGA - 450B/500B/600B/700B, NEX-B OCZ - ZT, ModXStream Rosewill - Glacier Silverstone - Bronze SFX XFX - XT Tier 6
Antec - Basiq VP Bitfenix - BPA Cooler Master - B2 Corsair - VS "orange units" EVGA - 430W/500W/600W 80 PLUS units FSP - Raider Silver Fractal Design - Integra R2 LEPA - MX-F1 NZXT - Hale82 V2 OCZ - Fatal1ty Rosewill - Hive, ARC (M) Silverstone - Strider Essential Thermaltake - LitePower, ToughPower, Smart series < 750W Zalman - GS/GT Tier 7 - Worst
Cooler Master - Elite series EVGA - 400W non-80 PLUS certified FSP - Hexa Thermaltake - TR2 These are all crap  
Currently awaiting more info
 
Some things on this list may not be perfect. Let me know if you believe a PSU is undeserving of its spot on here and provide links to back up your claim and it may be moved. 
 
Some helpful links:
 
How Many Watts Do I Need? - How much power will you need for your system? This guide helps you get a PSU that has more than adequate wattage for you.
80 PLUS Efficiency and What It Really Means - general guide to 80 PLUS efficiency and what it entails. Currently pinned on the Cases & Power Supplies subforum.
 

 
Ask any questions below! 
 
How do you even grade these things? ***
But I don't like Tier Lists!!!!111!!!!