yorkr@p4.cs.man.ac.uk (Richard York) (03/01/91)
I am about to buy an A540 + multisync monitor to replace my rather aged model B. I have heard many conflicting stories about multi-sync monitors, mainly concerning the limited number of modes that are usable with them. I have been told that this is because the lower screen modes of the arc have too low a vertical frequency rate, which the multi-syncs can't cope with. The monitor I am specifically interested in is the Taxan 795, the one with the sony trinitron tube. Apart from the improvement in picture area that this gives does this have any other advantages over the 775, 770+ etc, as well as some of the NEC ones, eq the one featured several times in the A540 literature. This is my first posting to usenet so lets hope it works ok! thanks, Richard York. -- :----------------------------------------------------------------------: : Richard York : E-mail : yorkr@p4.cs.man.ac.uk : : 1st year Computer Engineering : Janet : yorkr@uk.ac.man.cs.p4 : : Manchester University : :
bdb@cl.cam.ac.uk (Brian Brunswick) (03/01/91)
In article <yorkr.667760222@p4.cs.man.ac.uk> yorkr@p4.cs.man.ac.uk (Richard York) writes: > I am about to buy an A540 + multisync monitor ... > The monitor I am specifically interested in is the Taxan 795, ... Ok, I'll jump to this one, since I posted about the Taxan a while back. There are basically two parameters to a mode that affect whether it can be displayed by a given monitor - the horizontal sync rate and the fram rate. For a normal TV, the hrate is 15KHz, and the frame rate 50Hz - so thats 300 lines (These figures are approximate) The standard multisync modes like 20 double the hrate to 30KHz, and get 600 lines. The trouble with the 795 (which is otherwise very nice) is that it can only handle horiz rates of 30-57KHz, so any standard mode won't work, though the multisync ones will. However, it is possible to modify the format of existing modes to bring them into this range. This is done by loading a patch module - So if its a game that runs by some boot sequence that you can't get at, you're well Zogged, as certain people in Cambridge might say. There are two other issues here as well. Firstly, a standard Archi can only chuck pixels out at 24MHz, and with 8MhZ memory has a total memory bandwidth of about 25Meg/s. So not all existing modes can have their line rates increased sufficiently. There are hardware add ons which increase the max pixel rate to 36MHz, but you are still stuck. With a 540, I understand (check me on this) that it has such a mod built in, and also has 12MHz memory. So these figures go up, and its easier to fix things. Secondly, a lot of games take their timing from the fram rate. If your replacement mode uses a different frame rate, games will (attempt, and with an 540/ARM3 do quite well usually) to run fast. However, the frame rate can easily be reduced by leaving large gaps above and below the data, and adjusting the monitor to expand it vertically - make sure you get a version of the patch module with this ability. Basically, for the Taxan795, make sure you see it running before you buy, switch modes around, find out how to adjust it, and work out whether you personally can stand the irritation. But its a lovely picture - I recommend it. Brian.Brunswick@uk.ac.cam.cl Disclaimer. Short sig rules!