Monday, December 11, 2017

120Hz / 144Hz over HDMI 1.4 @ 720p? Yes, it's possible. HP ENVY 17t CTO-j000 Laptop & ASUS MG279Q

It's been just over 4 years since I purchased my HP ENVY 17t CTO-J000 laptop. It's mostly held up well but it's had it's fair share of problems. Since then, the fingerprint reader has ceased to function, the upper palm case has cracked from heat failure causing a cascade of problems including splitting the left side of the case intermittently cutting power to the NIC, and has seen LCD monitor failure that has painted a white line down the center of the screen (perfect for FPS gaming...).

However, the HDMI port still works. And playing FPS games on a 60Hz 17" LCD monitor with a line down the center is no fun. While my severely outdated desktop (2008 C2D E-8400 / 4GB RAM) remains dead with a failed motherboard my only choice is this laptop for general use and gaming. I don't really have the option to replace the desktop or the laptop with something modern so getting a new monitor is a step-gap. My monitor of choice ended up being the ASUS MG279Q


It's been asked numerous times on various hardware and gaming sites whether or not you can use a 120Hz / 144Hz monitor at those speeds over HDMI (but which version?). Most of the time there's an ambiguous answer leaning towards "no", but since you sometimes see "yes" it might work, right? 


HDMI 1.4 supports a maximum resolution of 4K or 4096x2160 pixels, most of the time at 30hz, but some have managed to get an image working at 60hz with NVIDIA's compression technology. So why wouldn't we get a 720p image over the rate of 60Hz? It seems there's arbitrary information stating that HDMI has strict caps on the refresh rate for each resolution, but there are multiple revisions of the standard.


In my case, I obtained an ASUS MG279Q monitor with a maximum specified refresh rate of 144Hz, with connections for HDMI (2), DisplayPort (DP) and Mini-DP. It's generally known that DP supports most ranges of configurations these days and is recommended for higher refresh rate support. This laptop only has HDMI output, and is specifically version 1.4.



From the HP Maintenance and Service Guide

Upon plugging this monitor into the laptop, I was presented with a maximum refresh rate of 120Hz at 1080p in the Windows 10 Intel HD Graphics Control Panel. I was very content seeing this as I had a strong feeling it would allow me to use the 120Hz setting at a lower resolution (something I could get most games to play at with a consistent frame rate) and a possibly higher refresh rate if I wanted to do some more tinkering.

The laptop supports a hybrid display adapter containing an Intel HD 4600 video adapter and a Geforce 740M. Most 3D acceleration is handled by the 740M.

By default, the monitor only reports a maximum of 120Hz at 1080p (at 1440p I am limited to 60Hz.) I do not have a way to test if the reported information is the same over DP at the moment. Setting the display to 1280x720, I was still limited to 60Hz so there's a mismatch of supported refresh rates being reported.  In order to do further testing, I needed to use the Custom Resolution Utility (CRU) to add entries to the resolution and refresh rate lists that don't normally appear. After configuring CRU to add a new entry for 720p @ 120Hz, I restarted the graphics driver using the CRU utility and I had a new entry in the display options. I was able to play Quake Live on this setting and reached a consistent 120FPS. 


Next, I created another custom entry with CRU for 1280x720 @ 144Hz. 


Again, after restarting, I was able to select this new resolution and refresh rate. 

720P @ 144Hz over HDMI 1.4


Unfortunately, I do not have any games immediately available that I can play with a consistent 144+FPS rate. Quake Champions only supports the default maximum resolution at 60Hz in fullscreen mode, but does allow borderless windowed mode to match the Windows desktop refresh rate (with and without V-SYNC) so in specific situations, I was able to see very smooth game play. 

At this point, we can see that there's likely a few things going on here that allow 120Hz / 144Hz refresh rates on older hardware. My only variable that is available to test would be the cable itself. Could older HDMI cables that do not support the 1.4-2.0 standard cause issues? 

For the sake of testing, I used two different HDMI cables, one is a generic cable manufactured around 2009 and the other is a cable by BlueRigger which is specifically labeled to support HDMI 2.0 (and prior versions). The BlueRigger Basic cable is linked through my Amazon affiliate program. 



BlueRigger Basic HDMI 2.0 Cable


The older generic cable would not work at 120Hz or higher. Cable standard certifications do matter. 


In order to get 720p resolution at 144Hz (or 1080p @ 120Hz), we need a few things working together: 

  • A display adapter with a minimum version of 1.4
  • A monitor supporting HDMI 1.4 and a 120Hz / 144HZ / + panel
  • An HDMI cable certified for 1.4 and above. 
  • Custom Resolution Software (CRU - Windows) and manual entries for these resolutions

Out of curiosity, I attempted to create custom refresh rates of 100Hz, and 120Hz at 1440p. Unfortunately, neither worked, so there is some point in this process (possibly the Intel HD4600) limiting the maximum resolution and rates. To push things a little further I configured 1440p at 65Hz and this was successful.


In the end, the answer is yes, 120Hz / 144Hz works with an HDMI cable (depending on your hardware.)



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Wednesday, January 25, 2017

Design flaw on HP ENVY 17t-j000 (possibly other models including 15 and TouchSmart)



It's been about 4 years since I purchased my CTO (custom to order?) HP ENVY 17t-j000 laptop. Ownership has not been without hiccups, but it still functions mostly as intended. 

This post is meant to highlight a design and manufacturing error in the base and top cover which I'm sure HP is well aware of. There are 5 mounting screws that have brass nuts which are set into plastic on the top cover (not the screen, but the palm rest surface) to keep them in place. 4 are for the lid & arm, and the other is for the base cover which keeps the unit from separating when opening the lid. This problem appears to be caused by long exposure to heat from the CPU fan and heatsink. Over time the plastic hardens becoming brittle and physical damage (like a drop or hard setting on a table) cracks the plastic. 


In my experience, this could have been a much bigger problem if I had not taken quick action and disassembled the laptop to try and resolve the issue. In short, the pieces of plastic became scattered around the board and one ended up in the exhaust fan. I didn't allow this to continue very long, but it's not a stretch to see that it could have jammed up the fan causing a potentially catastrophic failure. You could hear the fan banging around the plastic when tilting the laptop. 



In this photo, all of the plastic screw assemblies have cracked from heat. 


In my search to resolve this I ended up on HPs PartSurfer catalog and went through each part number trying to see if the plastic mount itself was available for purchase. Unfortunately it is not, and is part of the "Other PCA Assems" category. The part is called  "SPS-TOP COVER CURVE" which is the entire palm rest cover.  The part number is 720271-001 and is priced over $100 from HP.  I decided to check eBay and Amazon-  prices were similar there. Of course, there were some used pieces and they were marked as "for parts or not working" - what was wrong with them? Of course, busted plastic screw mounts. 


I was able to fish out all the broken pieces and reassemble the laptop and took a few pictures to visualize the issue. A word of advice: you do need to unplug the CMOS battery to disassemble the laptop so check your BIOS settings if (customized) applicable and record them. 


I'm no engineer, but my suggestion would be to create a wall with a thin metal shielding around the plastic screw area to prevent heat from getting in there, and also make sure that it is complete from the base to the top so that if plastic does break off, it cannot be scattered around the chassis. 



Plastic fragments

Another angle.


Without the screw the laptop separates


Unscrewed fan and blew out dust.


Tip: remove screws one by one and create a "chart" of where each screw goes.