Thin Clients and GPUs

[Ruptga]

I know the concept of a thin client is that you have a server that runs the OS and programs, and a connected computer (one that's usually about as old as the user), and they're thin clients because the server does almost all of the processing, and the client does almost nothing.
But how does that work with graphics? Say you're doing an internet cafe, is it more important to have a 1650pro in your server, or adequate GPUs in your thin clients? (Ignore for a moment the DX9 support that these 'adequate' IGPs/PCI cards probably won't have; I'm more asking about where the graphics calculations are done)

 

[Mark R]

In general, the server renders the display and then sends the image of the desktop over the LAN to the clients.

Because LAN is very slow compared to doing graphics locally, this generally means that thin clients are unsuitable for anything that requires real-time (or near real-time) graphics; e.g. videos, animations, interactive 3D, games, etc.

At work, we do have a rather special 'client-server' 3D graphics system for working with 'gigavoxel' images. The performance is good (5-10 fps, which is probably equivalent to having something like 7900GTX SLI on the clients) - but then the server cost over $100k and the 'thin client' software runs on Xeon workstations hooked up over a dedicated gigabit LAN. However, the reason for getting this system, was that it still runs pretty well on the cheap celeron/integrated graphics machines around the place - not just on the high-end workstations.

 

[Ruptga]

Well I don't really have a grasp of a gigavoxel, but I get the impression that it's pretty big. But you did answer my original question.
I know nothing done on a server will be as good as if it's done on the client, but the idea is to save money while still having a decent end-result for the users. I really wasn't thinking of anything Stateside or gamer-ish, but for computer labs in schools that a charity would be working with; basic internet and email, good enough that it won't lag down when those flashing catch the monkey banner ads come up (which I have seen happen on a PIII 500mhz). But the idea is that we could bring in an X2 with a 1300pro or somesuch, hook it up to twenty 6x86s or PIIs, and have twenty machines that work about as well as old Northwoods with integrated graphics. I just want to know that it will work well before I try to sell Grandpa on it, he's pretty minimalist on new technology.

 

[Nothinman]

I know nothing done on a server will be as good as if it's done on the client,

Depends on your perspective. The UI will be slightly laggier but things like email, web browsing, word processing, spreadsheets, etc all work fine remotely. I used to use Citrix semi-regularly at my last job and it wasn't bad at all and it's a god-send from an administrative standpoint.

But the idea is that we could bring in an X2 with a 1300pro or somesuch

The video card on the server doesn't matter at all, the only thing it'll effect is the server's local console.

 

[Mark R]

Originally posted by: ADDAvenger

I know nothing done on a server will be as good as if it's done on the client, but the idea is to save money while still having a decent end-result for the users. I really wasn't thinking of anything Stateside or gamer-ish, but for computer labs in schools that a charity would be working with; basic internet and email, good enough that it won't lag down when those flashing catch the monkey banner ads come up.

Unfortunately, animation and interactivity are the 2 things that don't work well on client-server systems. This means that animations will lag the system, unless it is exceptionally powerful.

We have a 'normal' client-server system at work too, with little Wyse terminals connecting to a terminal server. When those 'punch the monkey' ads come up, the clients grind to a halt. The reason is that animation puts massive strain on the LAN link - and everything lags up - because nothing can get past 20 frames per second of dancing monkey.

At any rate, these ads are all 2D based, so don't benefit much from the acceleration found on modern GPUs - which largely concentrates on 3D. This 2D stuff never touches the server graphics card - it goes straight to the client.

As for 3D acceleration - well some server systems support it (so can accelerate 3D rendering, and then send the renderd images to the clients) - I think some versions of Linux can do it, out of the box. However, with Windows I think you need to buy Citrix Server and a seperate 3D acceleration plug-in for that.

However, only a very limited server software packages support 3D acceleration. The vast majority will run any 3D using software rendering.

 

[Ruptga]

Hmmm, so what you two are saying is that a server will fix crummy CPU problems, but won't make any difference on the graphics end, so it would be better to run the clients off of an X2 with integrated graphics and take what we would have spent on a 1300pro and put it into PCI vid cards. That's not what I was hoping to hear, but I'm glad I found out before we put any money into something we don't need.

 

[Nothinman]

Yes, video cards on either end won't matter, everything is rendered on the server and pumped over the network to the client so the client just gets a bitmap from the server. Just install VNC on a box and then connect to it with the VNC client to get an idea of what we're talking about, Citrix and RDP are both faster and more effecient than VNC but the idea is similar.

 

[Mark R]

If all the clients are going to be doing is running as terminal clients - then you don't need an X2 really. The idea of a thin client is that the client doesn't do much - all the work is done by the server, all the client does is receive screenshots from the server and display them. This requires virtually no CPU power, and virtually no graphics acceleration.

Even a low-end sempron +integrated graphs would be more than adequate (just give it a decent amount of RAM - 256 MB or so). Of course, if you're going to be running other stuff (e.g. games), then you need to tailor your specifications to that.

The key point is to make sure that the server has enough CPU/RAM to handle as many instances of apps as needed, and enough network bandwidth to keep the clients fed. That means gigabit LAN (at least from server to switch) if you've got more than about 20 clients - otherwise things will start getting laggy when if several people indulge in punching monkeys at the same time.

The key points:

Server
CPU: Very important
LAN: Very important
GPU: Irrelevant

Client
CPU: Low importance
LAN: Moderate importance
GPU: Irrelevant

 

[Ruptga]

I mean the X2 is for our server, remember when I said Grandpa is technologically minimalist?

So then, I think I understand what's going on in the technical parts now. What do you think of, say an Xtenda X300, or their L200 terminals, or something like this that a techn-dummy could put together?