I managed to grab a Maximus XII Hero on amazon warehouse for $160 Well, this is the first red flag. I'm going to guess the reason it was returned, and the reason it was sold for 1/3 retail pricing, is that it never worked in the first place. Also, Z490 requires a BIOS update to run 11th gen, which I'm guess is another issue that needs addressed first. Answer from -UserRemoved- on reddit.com
Asus
rog-forum.asus.com › t5 › z370-z390 › rog-maximus-x-hero-q-code-quot-40-quot-always-show-at-the-mobo-7 › td-p › 766799
ROG Maximus X Hero Q-Code "40" Always Show at the ... - Republic of Gamers Forum - 766799
March 7, 2024 - ROG Maximus X Hero Q-Code "40" Always Show at the ... ... Hi ASUS ROG members, I bought an ROG Maximus X Hero motherboard and is curious about the Q-code shown at the motherboard 7-segment display. Each time I power up my PC, the Q-code shows "40". I restarted my PC and the Q-code shows "A0".
Reddit
reddit.com › r/buildapc › asus q code 40, no video out from gpu. 11 hours on this and i'm exhausted :(
r/buildapc on Reddit: Asus Q Code 40, no video out from GPU. 11 hours on this and I'm exhausted :(
August 4, 2021 -
Hey! So this is probably my last case resort before I start tearing the system apart and completely rebuilding it with a new motherboard. I recently picked up the bestbuy ASUS 3080 pc and decided to transplant the components with existing components from a ryzen 5, 580x build of mine (ram and psu into a new case, cooler, and motherboard. I managed to grab a Maximus XII Hero on amazon warehouse for $160 so I centered the build around that and it came pretty much brand new.
Now to what's been making me feel so defeated: I spent about 11 hours disassembling both PCs and building two of them again. However when I tried booting up the PC that I was planning on using as my main driver, it boots and cycles to asus post code 40 (which has something to do with waking from crashing) however nothing appears on my monitor. I replaced the 3080 with a 3060ti that I planned to put in the other PC for my brother to test if it was a video card issue, however the same issue persisted. All fans spin, no weird noises, and there's just no visual.
Does anyone know what's up? In the worst case scenario my motherboard is DOA which would be tragic. However I'm hopeful that this just has something to do with a BIOS update incompatibility due to the lack of either 11th gen support on this z490 chipset (although from my research there shouldn't be) or something to do with the 3080/3060ti being PCIE 4.0 in a PCIE 3.0 slot? Does anyone have any ideas for things I can try out outside of just replacing the motherboard?
Things I plan to try:
-
Removing ram sticks
-
Updating bios(?) no idea how since I can't get into BIOS
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Trying the old RX580
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Last resort, replacing the motherboard (I don't have any more thermal paste or sticky washers from arctic, so I'll have to figure out how to get more.)
Thank you so much for taking the time to read this, I'm sad and angry at myself for not testing on the bench before putting everything together and honestly just want something to display so I can work.
PCPartPicker Part List
| Type | Item | Price |
|---|---|---|
| CPU | Intel Core i7-11700KF 3.6 GHz 8-Core Processor | $529.99 @ Amazon |
| CPU Cooler | ARCTIC Liquid Freezer II 360 A-RGB 48.8 CFM Liquid CPU Cooler | Purchased For $140.00 |
| Motherboard | Asus ROG MAXIMUS XII HERO (WI-FI) ATX LGA1200 Motherboard | Purchased For $160.00 |
| Memory | Crucial Ballistix Sport AT 32 GB (4 x 8 GB) DDR4-3200 CL16 Memory | Purchased For $120.00 |
| Storage | Western Digital Blue SN550 500 GB M.2-2280 NVME Solid State Drive | $59.99 @ Newegg |
| Storage | Crucial MX500 1 TB M.2-2280 Solid State Drive | $114.99 @ Adorama |
| Video Card | Asus GeForce RTX 3080 10 GB TUF GAMING Video Card | $900.00 |
| Case | be quiet! Pure Base 500DX ATX Mid Tower Case | Purchased For $79.99 |
| Power Supply | Thermaltake Toughpower Grand RGB 750 W 80+ Gold Certified Fully Modular ATX Power Supply | Purchased For $60.00 |
| Prices include shipping, taxes, rebates, and discounts | ||
| Total | $2164.96 | |
| Generated by PCPartPicker 2021-08-04 10:23 EDT-0400 |
Asus X99-A Q-Code 40 sometimes - PCPartPicker
I have the mobo Asus X99-A and sometimes it boots with AA and sometimes 40 ?why i know q code 40 means somethings not right but im not sure how to fix it More on pcpartpicker.com
Q code 40 HELP - Republic of Gamers Forum - 587360
Hi folks I'm having a strange issue here. I have an issue where every time I power up my PC it doesn't turn on on the first boot ever! (well maybe 1/50 literally) but it always works perfectly fine when I hit the reboot button 100% of the time. Normally my Qcode says AA so I know it's not always ... More on rog-forum.asus.com
After turning on XMP, Q-Code 40 will appear when b... - Republic of Gamers Forum - 980364
If, after turning on XMP, the computer ... Q-code 40. Everything is normal. Close XMP, shut down the computer, turn off the socket power, turn on the socket power after 5 seconds, press the power button, the motherboard runs, the PC is fully turned on, Q-code A0. Everything is normal. Please tell me how to solve the problem that the motherboard will automatically stop for 3-5 seconds when the power is turned off and then turned on again. Asus ROG Maximus ... More on rog-forum.asus.com
ASUS Maximus VI Formula Q-Code 40? - Republic of Gamers Forum - 434043
All right, I Was going by this here is the link: http://www.hecticgeek.com/2012/12/disable-hybrid-boot-windows-8/ Post if this solves the code 40. ... ASUS MAXIMUS VI FORMULA - Intel® Core™ i7-4790K Installation Question in Other Motherboards 11-04-2025 More on rog-forum.asus.com
Videos
Top answer 1 of 4
1
Don't know if this has been resolved yet, but Asus Q-Code 40 means your PC has awoken from S4 sleep. What happens is in Windows 8/8.1 a feature called Fast Startup is on by default, it works by saving system info to a file upon shutdown so when you start your PC again, Windows uses that system info to resume your PC instead of restarting it.
To disable this, right click your start menu and go to Power Options, then select Choose what the Power button does, then under Shutdown settings you can disable Fast Startup. Also, disable Fast Boot in your BIOS as well, it will be in the boot section.
2 of 4
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Sorry to bring this post back from the dead but I'd like to know if there's any actual advantage from having Fast Boot enabled in BIOS as well has Fast Startup on Windows Power Options! Thanks in advance :D
PCPartPicker
pcpartpicker.com › forums › topic › 142061-asus-x99-a-q-code-40-sometimes
Asus X99-A Q-Code 40 sometimes - PCPartPicker
40 Q-Code: Pc was booted / boosted via a Windows controlled method (Usually from deep sleep, restart, Hibernation etc) Either way 40 or AA signify normal operation, so nothing to worry about with those two codes.
Asus
rog-forum.asus.com › t5 › other-motherboards › q-code-40-help › td-p › 587360
Q code 40 HELP - Republic of Gamers Forum - 587360
March 6, 2024 - ^^ Q-Code 40 is resuming from the S4 Hybrid state. Sort out the instability issue and this will be fixed. 0 Kudos · Reply · Post Reply · Related Content · Strix 675-E gaming Wi-Fi code 98 console input error in Other Motherboards 02-15-2026 · Crosshair V Formula-Z FF code in Other Motherboards 01-25-2026 · Bios Support in Z370 / Z390 01-10-2026 · Has my X-99 Pro failed or is it something else? in X99 11-28-2025 · Asus Maximus IX Hero RAM issues and code 55 in Z270 09-19-2025
Linus Tech Tips
linustechtips.com › computer hardware › cpus, motherboards, and memory
I have an issue with Q-code 40 always display on mobo - CPUs, Motherboards, and Memory - Linus Tech Tips
November 14, 2017 - Hi, I just build a new rig few days ago. What im facing now is an issue that Q-code always showing 40 on my Asus Strix x399 E-Gaming motherboard. My last rig used to showed Q-code AO on the motherboard and i think that is normal but now im facing the Q-code 40 and sometimes Q-code AA. I do lot of...
YouTube
youtube.com › watch
Asus Motherboards (Q-code 40 fix) - YouTube
I changed the title of the video because the feedback I have got is saying most if not all Asus motherboards have the same issue.Quick video showing how to f...
Published October 10, 2015
Asus
rog-forum.asus.com › t5 › gaming-motherboards › after-turning-on-xmp-q-code-40-will-appear-when-booting › td-p › 980364
After turning on XMP, Q-Code 40 will appear when b... - Republic of Gamers Forum - 980364
December 18, 2023 - Hello, CODE 40 indicates awaking from S3 Resume sleep states, and is normal functionality. Power cycles when changing certain petametres is also normal especially when it pertains to memory training, as some controllers require this.
Asus
rog-forum.asus.com › t5 › other-motherboards › asus-maximus-vi-formula-q-code-40 › td-p › 434043
ASUS Maximus VI Formula Q-Code 40? - Republic of Gamers Forum - 434043
March 6, 2024 - Nate152 wrote: Hello IBIubbleTea, code AO means your pc is working properly, code 40 means your pc has awakened from the S4 sleep state. I don't have my computer in sleep, it was a cold boot.
Asus
rog-forum.asus.com › t5 › other-motherboards › q-code-40-on-crosshair-v-formula-z › td-p › 672866
Q-Code 40 on Crosshair V Formula Z - ROG Forum - ASUS
March 6, 2024 - ASUS Crosshair V Formula-Z; FX ... WD 1TB; x18 DVR212D; 7SP1 ... Qcode 40 is not an error. It is a code indicating that the system is waking up from S4 sleep state....
Quora
quora.com › How-do-I-Fix-ASUS-Motherboard-Error-Code-40
How to Fix ASUS Motherboard Error Code 40 - Quora
Answer: The motherboard is the core factor that holds your computer’s components. So if the motherboard gets an error, everything falls apart. Asus error code 40 is a very common one. The error generally relates to the Asus motherboard issues which stop your device from functioning normally.
Asus
rog-forum.asus.com › t5 › other-motherboards › debug-code-40 › td-p › 540667
Debug code 40. - Republic of Gamers Forum - 540667
March 6, 2024 - Can you please provide us with your system components so we know what you use. So according to my motherboard user guide the 40 Q-Code is: System is waking up from the S4 sleep state. Does it show when you power on your system or later ?
Asus
rog-forum.asus.com › t5 › z170 › asus-maximus-viii-alpha-hero-qcode-40-cold-boot › td-p › 671450
asus maximus VIII Alpha Hero Qcode 40 Cold boot - Republic of Gamers Forum - 671450
March 6, 2024 - marcelmaria wrote: Dear fellow ... and there are several with this problem? Sincerely Marcel Q-Code 40 means your PC has awoken from S4 sleep....
Asus
rog-forum.asus.com › t5 › x99 › q-code-40-while-being-in-windows › td-p › 664995
Q-Code 40 while being in windows - ROG Forum - ASUS
March 6, 2024 - Yes it is "40" and fast boot is disabled and this q-code sometimes pops from a cold boot (no hibernation). But, yea win10 is installed in uefi mode so maybe win10 is doing something to the boot sequence, could that be possible ?
Asus
rog-forum.asus.com › t5 › amd-500-400-series › q-code-40-x570-e-gaming › td-p › 845356
Q Code 40 x570 e gaming - ROG Forum - ASUS
March 6, 2024 - I turned it off, so now it only shows during Post, which is how it should be and the code is gone. Thanks for that. ... [Motherboard]Fix FPS Game Launch Errors: Enable Secure Boot and Update TPM 2.0 (fTPM) on Windows PCs in FAQs (Motherboards) 3 weeks ago · ROG Strix X570-E Gaming in AMD 500 & 400 Series 09-26-2025 · Bifurcation for X570 Dark Hero? in AMD 500 & 400 Series 09-14-2025 · X570 E-Gaming not booting in AMD 500 & 400 Series 09-09-2025 · Asus Rog Strix x870e-e gaming Stopped working all of a sudden !!!
Reddit
reddit.com › r/amd › what does error code 40 really mean on c6h?
r/Amd on Reddit: What does Error Code 40 really mean on C6H?
April 20, 2017 -
Some C6H motherboard won't boot in some circumstances and all display error code 40. Restart the system solves it.
Top answer 1 of 5
1
First result on Google: http://www.tomshardware.co.uk/answers/id-2394345/error-code-asus-hero-vii.html#r15306984 . Different board but the code should be the same.
2 of 5
1
Apparently error code 40 isn't in the manual, so I guess the error code is some new thing from the new bios' that has come the last month or so. I vaguely recall having read from some Asus guy that they will add error codes with times, and that the codes in the manual won't be up to date that reason. I suppose, there is a chance that Asus has updated error codes in the online version of the manual for the Crosshair VI Hero board. I haven't checked.
Asus
rog-forum.asus.com › t5 › x99 › q-code-40 › td-p › 593138
Q code 40 ? - Republic of Gamers Forum - 593138
March 6, 2024 - But Q code read 40. I restarted and all is fine, Q code is now AA. Anyone know what would cause that? ... Check the manual - I believe it is a code for waking from a sleep state. Page 1-33 · ASUS Rampage V Extreme BIOS 4101 | i7-6950X | Thermaltake Core X9 | G.Skill F4-2800C16Q-32GRK | Cooler Master Nepton 280L | Dual Samsung 850EVO 500GB SSD | PSU: DARK POWER PRO 11 1000W | 3TB & 4TB HDD | NVIDIA GTX Titan X | ASUS 24x DVD±RW Drive | Win10 Pro
Asus
rog-forum.asus.com › t5 › other-motherboards › rampage-iv-black-edition-q-code-40 › td-p › 421783
Rampage IV Black Edition Q code 40 - ROG Forum - ASUS
March 6, 2024 - Praz wrote: Hello 0x40 has nothing to do with memory speed or the use of the XMP setting. It is a normal value when restarted from the S4 state. This is explained in the motherboard's manual part of which is copied below.
Reddit
reddit.com › r/asusrog › q-code 40 on asus rog x570-e gaming mb
r/ASUSROG on Reddit: Q-CODE 40 on ASUS ROG x570-E Gaming MB
June 8, 2020 -
Hello anyone keeps seeing Q-code 40 on the MB ? everything is running fine, just curious - I cannot find the 40 code in the manual. Thank you
Asus
rog-forum.asus.com › t5 › x99 › q-code-40-with-windows-fast-boot-enabled › td-p › 663959
Q code 40 with Windows fast boot enabled - Republic of Gamers Forum - 663959
March 6, 2024 - Legolas wrote: Reseat all components on your motherboard. Press MemOK to set memory to SPD and see if you get the problem? Did you change CSM to enable and try to boot again and see if it happens? Haha...just my luck. I was wrapping up work and said to myself, ok now that I have time, lets try it out with CSM. Rebooted the machine and: https://rog.asus.com/forum/showthread.php?84296-Raining-Q-codes-)&p=584646#post584646 Damn...