G450+KVM switch=shaky image+ghosting, other graphics card works fine

[TomR2]

Hi!
I have the primary output of a G450 connected to a Linksys 2-port KVM switch. The problem is that the image is unstable (shaking) and there's some ghosting too. Without the KVM switch these symptoms do not occur. I'm using special KVM cables included with the switch so it's not a matter of bad cables. I think the problem is caused by the KVM switch not getting enough power from the G450 output (the KVM switch draws power from the KVM cable connected to the PC), because the same symptoms occur when I don't have all 3 connectors (keyboard, videao, mouse) on the cable connected. The other video card connected to the KVM switch is a Diamond Viper V550. With this card the image doesn't suffer from such problems. So my guess is that the power output from the G450 just doesn't suffice for the KVM switch. The question is: is there any way to safely increase the power output of the G450's primary output?

Regards,
Tom

[Greebe]

The output of the G450 is a standard 1v P-P signal... increasing it would put it over spec... talk to the manufacture of the KVM switch... it's causing the problem

[TomR2]

Thanks for replying Greebe.
However, I don't see how it can be the switch when it works fine with the other graphics card.

Regards,
Tom

[Greebe]

The Diamond Viper isn't exactly known as a quality card... one of the reason Diamond got out of the biz of making Gcards... crap quality, crap support, crap drivers.

And I for one am sure glad they did!

[TomR2]

Greebe, that makes my point even more valid! How come a crappy card works fine, and a good one (I assume you don't consider the G450 crappy) doesn't?

Regards,
Tom

[Greebe]

The crappy one is outputing to high... ie out of/above/over spec video signal. Since this is occuring then the KVM switch is causing the signal to be whacked for card(s?) that function correctly.

Proof is that it works fine with the KVM switch removed and connected directly.

Now if you had (have?) access to an Oscilloscope I'd have you terminate each of the R/G/B signal pins into a 75 ohm load to verify the signal level on each card... this would be proof prositve of who was to blame.

I'm not saying that it couldn't be the G450 causing the problem neccessarily, but based on your current statements this leads me to the logical conclusion that the problem is with the KVM switch and not the card.

[Jammrock]

I've had KVM problems as well. I have a few tips that may help, but no garuntee. First off, the video cables that are in the KVM 'cable kits' are total crap. They aren't shielded properly and no noise reduction devices are attached. Add that to a longer total cable length and KVM's become noise magnets. And the cleaner the signal, the more noise will affect it.

Belkin makes good shielded cables that I use on my test monitors and KVM's. Check these parts out. They are a bit pricey, but they work:

http://catalog.belkin.com/IWCatProductPage.process?Merchant_Id=&Section_Id=16&pcount=&Product_Id=14676&Section.Section_Path=%2FCables%2FMonitor%2F

http://catalog.belkin.com/IWCatProductPage.process?Merchant_Id=&Section_Id=16&pcount=&Product_Id=17279&Section.Section_Path=%2FCables%2FMonitor%2F

http://catalog.belkin.com/IWCatProductPage.process?Merchant_Id=&Section_Id=16&pcount=&Product_Id=17305&Section.Section_Path=%2FCables%2FMonitor%2F

http://catalog.belkin.com/IWCatProductPage.process?Merchant_Id=&Section_Id=16&pcount=&Product_Id=14679&Section.Section_Path=%2FCables%2FMonitor%2F

The full cable list is here:

http://catalog.belkin.com/IWCatSectionView.process?IWAction=Load&Merchant_Id=&Section_Id=16

3 things to watch for when buying cables from Belkin. 1) make sure the genders are correct. The web site has the cable gender for both sides of the cable (does anyone else find that comment disturbing?). 2) Shielding. You are ususally safe with the monitor replacement cables, but the genders may be wrong. Some of the extension ones are good, but only the more expensive ones work really well. 3) Price! Belkin cables can get really expensive, really fast! The more shielding and distance you need the higher the price tag gets.

Hope that helps.

Jammrock

[Greebe]

Instead of those cables Jammrock, I'd suggest Belkin's Pro series High Integrity series cables only...

http://catalog.belkin.com/IWCatSectionView.process?IWAction=Load&Merchant_Id=&Section_Id=16

[Jammrock]

I had a couple of High Integrity cables in my list! I also had some options under $50 in there as well

Jammrock

[Greebe]

By all means shop around for these cables... I've seen their 10' Pro Series extension cable go for $7 online at a discounter, where Belkin sells them for $30!

[jImbEam]

While we are talking about KVMs, can anyone recommend a good one? Mine makes my G400's output "ghost" and it bugs me.

I have a Linksys PS2KVMSK.

jImbEam

[K6-III]

Cybex Switchview

[Rob100]

I have recently bought an Adderview 4 port Gem which although is classed as an "entry level" KVM I'm very impressed with it. Good features and I have noticed no degregation of the display - I was worried about this before I bought it.

I have all 4 ports in use.

1) Marvel G400 in my DTV box
2) Amiga A1200 ;-)
3) Voodoo 3 3000 AGP - gaming/cd writing box
4) Crappy old S3 Virge PCI card in my server

I'm using Adders 3in1 cable sets. Monitor is running @ 1152x864 85hz from V3 and G400 and looks great to me.

Rob.

[Clevor]

Check out Cyberguys.com

I am using an Iogear GCS14 I got from Cyberguys.com for $135. Now that sounds like a lot, but it includes 4 sets of high quality keyboard/mouse/VGA cables (color coded), and you know those run $27 a piece. I think the thing has a 3 or 5-year warrantee.

I got the 4 port switch because I run both AGP and PCI video cards off two computers.

I am using this switch with a Matrox G400 and G450 PCI, and I don't notice any dropoff in image quality at 1600x1200 (the switch will do 1920x1440, by the way, which is why I got it).

Plus, Cyberguys.com is a great place to do business for peripherals! A lot of their stuff is generic, but besides being dirt cheap, I've never had problems with them. I used to use Belkin a lot, but not anymore. If you need to return a cheap item, they tell you to keep it and they refund your money.

[TomR2]

Originally posted by jImbEam
While we are talking about KVMs, can anyone recommend a good one? Mine makes my G400's output "ghost" and it bugs me.

I have a Linksys PS2KVMSK.

jImbEam

That's the one I have too.
jImbEam, what other card do you have connected to it? What's the image quality?
I investigated a long time before buying this switch and read good reports about image quality (the only thing that really matters to me, I don't really need mouse and keyboard sharing). Bad decision after all it seems. The problem is that around here (in Belgium) it's very hard to find most brands of KVM switches. Had to search a long time to find the Linksys one. Maybe I'll try other cables...

Thanks everyone for the replies!

Regards,
Tom