DVI has three different variations:
DVI-D: digital signals only
DVI-A: analog signals only
DVI-I: 'Integrated': both digital and analog signals

DVI-A and DVI-I basically have a few pins that literally have a VGA signal on them.
So you can use a simple passive converter from VGA to DVI-A/DVI-I.
DVI-D basically carries a HDMI signal.
With a VGA to DVI converter, you actually convert the analog VGA signal to a digital DVI/HDMI-compatible signal, which means you can also use it on HDMI-only or DVI-D-only devices.
DVI-A/I will probably be phased out over time, many devices currently only support HDMI or DisplayPort, nothing analog.

DVI isn't a signal specification, it's a connector specification. Full DVI-I allows for both analog and digital signals. Your 'simple' adapter simply takes the analog signals from VGA and routes them to the analog pins on the DVI connector. Your display device still gets an analog signal and is responsible for the ADC. This VC160A does ADC itself, so the analog input gets converted to digital output on the digital pins of the DVI connector.

The advantages are simple: if your display device doesn't support analog input (i.e. if you want to further convert from DVI to HDMI or DP), or does so very badly, this converter solves that. The disadvantage is that you're stuck with whateer the VC160A itself does (no 'auto-adjust button' anymore). It claims to be 'smart' but just how smart remains to be seen - that said, Aten and VanCryst are very reputable brand names and are used in professional broadcast environments. It sounds pretty legit, although I still mistrust the complete lack of controls.

Given that your current setup actually does the job, I'd not soon recommend that VC160A, although depending on price (what does it cost?) it might be a very good solution if it doesn't.

Thx for the very helpful replies. The Converter costs 120 €. I think about trying. If it doesn't improves something it will go back.

So spend EUR 120 to avoid having to press a button every time you boot... well, if it's worth that much to you, go right ahead.

dionb wrote:

So spend EUR 120 to avoid having to press a button every time you boot... well, if it's worth that much to you, go right ahead.

As I said... If there isn't any improvement... Just no need of pressing a Button anymore is no improvement (for that price)

I also sometimes have vertical blurry zones (don't know how to describe it otherwise). The auto adjustment doesn't fix that in every case. This doesn't appear when using a dvi source.
.

Sampling errors, probably. VGA as a signal doesn't have horizontal resolution, per se. It's a continuously varying signal that just happens to be generated from a digital source with a matrix of discrete pixels. This makes it difficult to convert back to digital because there's no clock or other indication of when the RGB values should be sampled to re-generate individual pixels. Displays with analog inputs have to guess where those sample boundaries are, based on knowledge of standard resolutions and the image data they're able to capture and analyze. It can be an imperfect process. The new conversion box will have the exact same struggles, but it may be better or worse at coping with them.

The best way, in terms of image fidelity, is to use something like the OSSC, which can be configured by hand. You tell it (essentially) the horizontal and vertical resolution, the point on a horizontal line where the image begins, and the number of non-image lines used for vertical retrace. With this, it knows how many samples it needs to take, and about when to sample. If you get all of this correct, and the signal is consistent, you will get a near-digital image in return -- with a certain amount of variation in the color of every pixel stemming from the imprecise nature of analog signals. (Usually benign, but this is almost completely dependent on the quality of the VGA DAC.) Now, this isn't very convenient when you're setting it up -- lots of manual adjustments and technical timing details to deal with. But once it's set, and saved as a preset, it works great. If you're an image purist, it's definitely the way to go. Otherwise, just press the Auto button on your monitor again and see if it looks better.

Most of those VGA to DVI or HDMI adapters do not support anything below 640x480 and definitely do not support some of the DOS refresh rates.

And some of them that do, don't have the proper adjustments to scale the image to the proper size or have the whole image on the screen.. and the scalers in a lot of them are pretty horrid.

Lazar81 wrote:

As I said... If there isn't any improvement... Just no need of pressing a Button anymore is no improvement (for that price) […]
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dionb wrote:

So spend EUR 120 to avoid having to press a button every time you boot... well, if it's worth that much to you, go right ahead.

As I said... If there isn't any improvement... Just no need of pressing a Button anymore is no improvement (for that price)

I also sometimes have vertical blurry zones (don't know how to describe it otherwise). The auto adjustment doesn't fix that in every case. This doesn't appear when using a dvi source.
.

That is a problem with the scaler built into your monitor.

Thx again for the replies. So I might have a look at this Aten Thing and hope the best. I will tell.
I googled for that ossc. Never heard of this before. It looks like it is also very expensive. 160 € and above. An advantage is the amount of possibilities to connect older sources like VCRs or gaming consoles. I will think about.

The OSSC is a godsend for a specific kind of user. Retro enthusiasts who care about image quality and near-zero lag. It'll do component video, RGB video, VGA, handle all kinds of sync types, etc. It's designed mostly for SNES, Genesis / MD, PSX, etc.. but vintage computers work great with it as well, provided your monitor is OK with HDMI carrying PC resolutions and 70Hz. My TV is fine with that, so it's hands-down the best thing out there - very flexible and great image, if you're willing to put in the effort of configuring it properly. It's about 75% plug-and-play, so if that's the priority, it's probably not a great fit.

I've used a few of the generic Composite / S-Video / Component / VGA to HDMI scalers, and most of them suuuuuuuck. I've got a Startech video-to-VGA box that looks soft and often noisy, and a Geffen VGA / RGB / Component to DVI that looks like mush. (IMO, Geffen make complete garbage and don't support it worth a crap either. Lesson learned.)

But, some of the VGA-to-HDMI (or DVI -- same difference) converters work well enough. I have a tiny one I use for guests at work that come in and want to project video from a laptop with only VGA ports. It does the trick, but it's a converter not a scaler (so the monitor still has to scale to the native panel resolution) and I never really scrutinized the video quality. It technically worked, and I was happy with that.

So, for the Aten... only way to know is to try and see. Or I guess there are reviews on some of those fancy websites now. So two ways.

Unfortunately i only found a single 5 star rating on Amazon for the aten. So I ordered it and will have a look. I intend to make some screenshots and post them here.

If I don't like it I will try this ossc device.

May i ask you why don't you consider the option for another cheap/used graphics card with Dvi output?

The ti 4200 already has a DVI Output. But the problem is, that the picture is exclusively sharp in the highest resolution 1600x1200. Going below that results in an overall blurry picture. Until now I haven't found anything to get lower resolutions as sharp as with VGA.

Lazar81 wrote:

The ti 4200 already has a DVI Output. But the problem is, that the picture is exclusively sharp in the highest resolution 1600x1200. Going below that results in an overall blurry picture. Until now I haven't found anything to get lower resolutions as sharp as with VGA.

And you won't. It is the nature of how LCD monitors work.

Well.. there is a way.. .but you will just end up with a tiny picture in the middle of the screen in however many pixels the resolution you are sending to the monitor is.

Other than that, you are dealing with the scaler and there are not that many scalers that are all that good. Even then you will not get a super crisp picture.

The only resolutions that will be better but still not perfect are the ones that are exact square divisions of the native resolution of the monitor you are using.

So for a 320x200 resolution, these would look ok if your LCD had any of these resolutions as its native resolution:

640x400

1280x800

2560x1600

For 320x240, these native monitor resolutions would look ok:

640x480

1280x960

2560x1920

CRTs are better about the lower resolutions not looking blurry, but they too were always sharper at the max resolution as well.

Depending on the scaler, you may also be able to get some letterboxed resolutions so it will make the picture smaller, but it will look better.

See if your monitor has a setting to turn of the "fit to screen / full screen" mode.

Ya, I already presumed that. But would this ossc do the job so much better than the monitors built-in scaler?

It does a significantly better job than my TV's scaler, mostly since the TV is optimized for video (not graphics) sources. I haven't compared it side-by-side to my PC LCD monitors. They always seemed to do OK at scaling -- good enough that I've never noticed them being deficient.

The OSSC caters to the "I want sharp pixels in my retro games" crowd, though, so it's likely to be the best option if that's what you're after. By what margin depends on your monitor. Either you are really picky (no judgment - we're all picky about something), or your monitor's scaler is really bad. Either would be fixed (as much as is possible) by using the OSSC. The Aten probably wouldn't be significantly better than an average monitor's internal scaler. Yours would have to be pretty bad for the difference to be appreciable.

So the aten unit has arrived today. I had a first look and it has indeed buttons for something to setup. I will tell how it works.

So here is my summary:

I will send this unit back for several reasons.

Pros:
- The vc160a puts out a very clear and sharp picture, so the blur in lower resolutions is totally gone
- it has screen positioning buttons at the bottom and a certain position for each resolution can be saved

Cons:
- it is extremely laggy (it isn't even able to show up a picture during the bios boot screen)
- there is irritating flickering at the right end of the picture... ALWAYS
- it is very expensive, I would expect far more

So overall it was a disappointing experience.

Yeah, I feel ya. That has unfortunately been my experience with most "this to that" video converters. I'm extremely skeptical these days. I went through two different boxes just to inject external audio into HDMI. How hard is that to get right? Stuff is cheap now, but it's also overwhelmingly junk.