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Monitor help- scan rates, dot clock, etc.

383 Views 9 Replies 3 Participants Last post by  DaveFi
I've been looking to upgrade my PC monitor to 22", and I'm not quite sure what to get.

The Iiyama HM204DT has been getting some good buzz, along with the NEC/Mits 2070, but costs a little bit more. The one thing I noticed about the Iiyama, is that even though they use the same tube as Mits/Nec, the scan rate is much higher-

The Iiyama's ($600) specs are-

H 30-142kHz V 50-200Hz

The Nec/Mits (~$530 @ Dell during deal) is-

H 30-140kHz V 50-160Hz

Both monitors have a 390 MHz Pixel Clock.

How does this translate to PQ? What about resolution and refresh rates? Can I even do the ultra-high res the Iiyama will technically achieve and still view the picture?

On the cheaper side, I noticed newegg is selling the Philips 202p4 for $450 shipped. This one also uses a "TrueFlat" monitor (not sure of the brand), but only does H 30-130kHz, V 50-160. 320 MHz Pixel Clock.

I guess what I'm really asking is, at what point do the specs become meaningless? Certainly the Philips monitor looks like the best deal, but the specs for the Iiyama are so far ahead of the others, would it be worth the extra money if I can run 1600*1200/120Hz? (The Philips can do that res at 97Hz, which seems good anyways).
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You need to determine at what refresh rate you can't detect flicker. It varies from person to person, but VESA has set the flicker free standard at 85Hz. Some people can't detect flicker at 70Hz and some can detect it at 100Hz. Use your peripheral vision to check. Set your desktop to a low resolution running 60Hz refresh and increase the refresh until you can't see any flicker. This is your flicker free refresh rate. If the monitor in question will support the necessary resolution at your flicker free refresh, then it should be usable.

The evaluation of picture quality is for your eyes only. Also, consider the size, weight and power consumption.

Maximum resolution may be nice and high, but if you are always running [email protected] flicker free refresh rate, then it really doesn't matter that the monitor can run [email protected] flicker free refresh rate.
Thanks- I was thinking along the same lines.

The Philips monitor is looking better and better. The Pixel Clock is actually 360MHz, and it can handle 1600*1200/100Hz. I like 100Hz alot, and seem most comfortable at it. I don't think anything much larger than that resolution is suitable for
I have a Philips 109b 19" shadow mask ($225) and it is very small. The casing is closely formed around the neck and it is very shallow. Good performance for the money. The Philips 202p will do [email protected]85Hz(according to the .pdf you linked). The Iiyama will do [email protected] It's interesting that the Philips is only down 5Hz to the Iiyama at 2048x1536. But, if you need 100Hz, then you need the Iiyama or NEC or maybe Cornerstone .
Oliver, the modes listed are just presets in the monitor's DDC firmware, it's not the maximum possible resolution/refresh rates. To figure that out you have to go by the scanrates.

I know there is some formula to figure such a thing out, I forgot how to do it. I'd be interested to find out what the Iiyama's absolute maximum refresh rate is @ 1600*1200. I suspect it's ~ 120Hz. That's damn good.
Refresh rate is not the only thing which determines "flicker". The phosphor persistence plays a big part as well. If you are doing flicker tests, try it with a solid white background.

You probably don't want to run at the max possible settings. If you set your refresh and resolution too high, the higher bandwidth signal can "bleed" more on the cables, and interface connectors along the way. This translates into some ghosting. Try a black desktop and look carefully at the fonts under desktop icons. Do you see a faint ghost image of the letters to the right of each? If so then you may want to reduce your refresh / resolution.

As much as I hate flicker, I still run everything at the range of 72-85hz because higher refresh rates starts to introduce other problems.

Some VGA cards will disable hardware assisted overlay buffers if the refresh rate is too high because the GPU is too busy redrawing the image.

Many monitors will show a "maximum" resolution and refresh rate settings as well as a "suggested optimum" settings. If they offer an "optimum" recommendation, I suggest you folllow it... It is often the closest setting that matches the actual resolution of the shadow mask (or aperture grille) in the CRT.

[email protected] is a good target for a modern VGA card with a recent vintage 21-22" monitor.

I am very happy with [email protected] on a GDM-FW900 24" wide (16:10) monitor.
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If anyone's interested, here's a page showing the Iiyama's maximum refresh rates at different resolutions.


As you can see, it can do 1600x1200/113Hz. If the Philips uses the same Mitsubishi tube I'll probably go with that and save $150.
Iiyama recommends a resolution/refresh rate of [email protected] for the HM204DT. Seeing that the Philips has a horizontal scanning frequency of 130KHz, it's maximum vertical scanning frequency would be [email protected] So, running the Philips at [email protected], would be awfully close to it's theoretical maximum. You could try it, but I think Philips wouldn't recommend it.
I'll run a little less, it's no big deal. The tube is the thing, and seeing that they all use the Mitsubishi Diamondtron tube, after a certain point the PQ starts to become blurry.

Right now I run my old Princeton EO90 @ 1152x864/100Hz, and it maxes out ~ 103. It looks fine. Anything over that resolution is too blurry.

Now it's down to price/performance- Is the Mits 2070 worth $70 more than the Philips? Is the Iiyama worth $150 more?
Thanks for the help- I decided to go with the Philips after it was confirmed it used the Diamondtron tube.

Newegg shipped it the day I ordered. Nice.
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