Are HDMI to DVI and Displayport to DVI adapters a good idea? - Page 1
Forum section: electronics / general

author: dentaku
author_rank: Frequent Contributor
timestamp: March 07, 2020, 10:12:01 pm
content: I'm finally going to build a new desktop PC and since my main monitor (Dell 2209WA 1680x1050 WSXGA+) only has DVI-D and VGA ports I was wondering if HDMI to DVI adapters OR Displayport to DVI adapters are worth using?I don't want to put a video card in this computer because it's not a gaming PC plus is just uses more power, creates more heat and adds more fans that end up making more noise.I'm going for the quietest computer I can build without using loud gamer hardware covered in annoying fans and flashy LEDs.QUESTION: Do these adapters cause any problems like image degradation or compatibility problems? I mean, it's a digital signal so it's not like analog where the quality of the adapter or cable can affect the image.Most of the newest motherboards don't seem to have DVI ports on them so I will probably need to use an adapter of some sort.According to this website HMDI to DVI is simply a matter of connecting the correct pins together so it's not like the adapter has any smarts in it. I guess you call it passive.https://pinouts.ru/Video/hdmi_dvi_cable_pinout.shtmlI'm not sure about Displayport and if it's more complicated to get a simple adapter. I know they're available but I can't tell if they're just a case of having the right pins connected together like HDMI or if the adapter needs some active circuitry inside it.

author: Halcyon
author_rank: Unknown
timestamp: March 07, 2020, 11:38:59 pm
content: Quote from: dentaku on March 07, 2020, 10:12:01 pmImage degradation: No.Compatibility: Maybe.Generally speaking, there are absolutely no issues or downsides to using these adapters. In fact a lot of the big brands like HP and Dell ship these kinds of adapters with some of their commercial-grade monitors.The problem I have run into is that they aren't always "bi-directional". What I mean by that is they might convert one way, but not the other. I ran into some issues with Dell DVI to DisplayPort adapters. They would convert a DVI signal which can be used on a monitor with DP (or the other way around, I can't recall now), but the opposite didn't work.

author: dentaku
author_rank: Frequent Contributor
timestamp: March 08, 2020, 03:29:50 am
content: The reason I've been looking into this stuff is that the Asus Prime Z370 board HAS a DVI port but only supports Gen 9 processors with a BIOS update.If I was to get a 9th gen i7 and the motherboard I get doesn't have the newest BIOS straight form the factory I won't be able to flash it because I won't have a CPU that works in it YET.I see that there's a Prime Z370A ii version so I'm checking to find out if maybe these newer revisions all have the update straight from the factory.I see there's also a Prime Z370P and P ii.

author: Munich
author_rank: Newbie
timestamp: March 08, 2020, 04:00:02 am
content: I run at least 2 external monitors on every laptop in my lab, 4 laptops running at any one time, every one is connected to either an HDMI or DisplayPort on the laptop, to a DVI or VGA port on the monitor as all of my monitors are rather "dated". The only problems I notice is that with certain VGA cables, if I am doing some high power testing on the bench, I might see a little interference in the picture. However, this is probably more the fault of the cables as they are cheap-as-dirt cables, I could get much better ones. Other than that, zero problems, and I really don't notice any difference between the VGA and DVI. In fact, the only difference I notice in any way is the color differences between all the different monitors

author: jc101
author_rank: Frequent Contributor
timestamp: March 08, 2020, 12:12:15 pm
content: Quote from: dentaku on March 08, 2020, 03:29:50 amWorth checking if the Asus boards have a USB port that can be used to flash the BIOS without a CPU. I had to flash the BIOS in my Gigabyte board to support the CPU going into it, it wouldn't boot otherwise. It was just a case of having a suitable stick plugged in before applying power, then it updated itself.

author: wraper
author_rank: Unknown
timestamp: March 08, 2020, 12:23:42 pm
content: HDMI to DVI adapters are simply wires going straight from one connector to another. Actually HDMI and DVI have the same signal, just that HDMI also can have extensions like audio, and higher clock rate added in later revisions. DP++ to DVI adapters (passive) have voltage level shifter IC inside. But DVI signal itself which is completely different from DP is generated GPU itself, it's just that voltage level is different thus it needs level shifter. There are also active adapters but those are not needed unless you need to connect dual link DVI input (used for 2560x1440+ resolutions) to DP output.

author: janoc
author_rank: Super Contributor
timestamp: March 08, 2020, 02:24:27 pm
content: Quote from: Halcyon on March 07, 2020, 11:38:59 pmThat's actually a fairly misleading statement.HDMI-DVI is generally fine, because that is only a passive plug adaptor (plus you lose things like sound when converting from HDMI to DVI, because DVI doesn't have these).However, DisplayPort <-> HDMI/DVI or anything to VGA can and does have issues, depending on the adapter.These are active (there is some sort of converter IC inside) and depending on what you have bought it may or may not work, may not support the resolution/refresh rates you want, the image quality may suck (e.g. when converting to VGA).Worse, some cheap ones may even fry your HDMI port. Many draw current from the 5V pin in the HDMI socket, which is rated for only about 50mA - and there are some HDMI-VGA converters that need over 100mA to function. I have encountered this problem on both my RPi and my TV set-top box HDMI outputs.Better designed adapters use ICs that are less power hungry and/or have a connector for external power but some crappy ones don't - usually with a bit of care you can crack the case open, break the power connection to the HDMI plug and feed in 5V from a USB port to solve the problem. The ones converting from DisplayPort are generally better because DP is able to source more current and these issues don't happen there.Another problem you are likely to encounter is that many of these adapter dongles don't translate/pass DDC info, so your PC/signal source will not see the capabilities of the monitor connected but of the adapter. Most often it isn't a big problem but it can happily break stuff like VR helmets - the computer will claim it is not connected because it can't detect its DDC info.Also if your are planning to play Blurays, you will have problems with HDCP that these dongles don't support (for obvious reasons).If you can avoid having to use such adapters it is always better.

author: mariush
author_rank: Super Contributor
timestamp: March 08, 2020, 02:57:56 pm
content: 1680x1050 is within 1920x1200, the maximum supported by DVI Single Link and plain HDMI ... so basically, any passive HDMI<->DVI adapter should work fine, as the adapter just connects wires between the two connectors.You should be able to find this kind of adapters for a few dollars locally :https://www.amazon.com/AmazonBasics-HDMI-DVI-D-Adapter-2-Pack/dp/B06WVSLSP3/You can install these adapters at either end ... on the monitor (and then use a hdmi cable between video card and monitor) would make most sense.You can also get a dvi-hdmi cable for about the same price :https://www.amazon.com/AmazonBasics-DVI-to-HDMI-Cable/dp/B014I8UQJY/

author: Mechatrommer
author_rank: Super Contributor
timestamp: March 08, 2020, 04:52:30 pm
content: due to rush requirement, i snapped my ownDIY DVI to HDMI cable hereto test my PC system. while at the same time ordering and waiting few adapters to arrive. by the time the order arrived, i got the diy cable working and also now a hoarder of plethora of adapters i can pretty much convert between any VGA <-> HDMI <-> DVI <-> DP using my adapters collection (if they perform what they are claimed to be) all about ~$20.. back to your requirement, if you can wait the $5 order, then just wait for it, you can save some time playing with kids or wife or save some eye strain and avoid infertility risk from lead poisoning... ymmv.

author: dentaku
author_rank: Frequent Contributor
timestamp: March 10, 2020, 02:00:46 am
content: Quote from: jc101 on March 08, 2020, 12:12:15 pmInteresting...I just checked and it looks like that feature is called Asus Flashback which it's only available on the higher end motherboards.

author: dentaku
author_rank: Frequent Contributor
timestamp: March 10, 2020, 02:09:37 am
content: Quote from: Munich on March 08, 2020, 04:00:02 amI hate VGA and can tell the difference between it and modern digital connections but I now see that I shouldn't have any trouble with a passive HDMI->DVI adapter since it's just a pass-through.Some people also can't tell the difference between different font smoothing methods or aren't bothered by bad refresh rates or slow PWM on LEDs either.Those are all things that really bother me.

author: dentaku
author_rank: Frequent Contributor
timestamp: March 10, 2020, 02:12:16 am
content: Do you have any recommendations for a decent quality HDMI->DVI adapter?I'll use the Displayport on my seconds monitor because it already has that connector anyway.

author: oPossum
author_rank: Super Contributor
timestamp: March 10, 2020, 02:17:59 am
content: Get a HDMI to DVI cable from a reputable source.For example...https://www.monoprice.com/product?p_id=2218

author: dentaku
author_rank: Frequent Contributor
timestamp: March 11, 2020, 10:05:34 pm
content: I found an HDMI to DVI adapter for $10 at The Source this afternoon so I tested it with a laptop which has an HDMI and it seems to work fine on both monitors. Even the older 1680x1050 Dell worked.