Wikipedia has the answer for the 2408

Right, but "Desktop" on the 2408 is simply a colour balance preset, isn't it? Doesn't seem to do anything other than switch to some rather dubious colour rendering.

Tell me you don't have to put up with a preset colour balance on the 2407 just to switch the processing off? 

If all the Genesis does is colour re-mapping, I don't see how it would cause any significant lag or sharpness problems.

I think it's whatever does the sharpening and scaling that causes the lag (and the "sharpening" issues). For instance, in the movie world, scaler-deinterlacer chips are well known for causing a frame or two's delay to video, because of the time it takes to process the data. That would correspond to about 20-40ms of lag. That may not sound like much, but it's not difficult to see when video is one frame out of sync with audio, and slipping by two frames is horribly obvious.

I haven't had to deal with this stuff for a while, but from what I remember, I think Genesis make scaler chips too. 

gpro, do you think this Genesis color correction feature has been implemented within the 2408?

if it's been implemented, perhaps benching for lag time, at different preset, is a worthwhile exercise.

the Genesis link talks about about color space conversions.

"In order to enhance the color and contrast ACM transforms the video signal from the native red/green/blue (RGB) color pace into the luminance/chrominance (YUV) color space"

I noticed an apparent improvement to lag using the HDMI input vs. the DVI input, i.e. I never measured it. After retesting, it does not seem like a dramatic improvement. I don't use HDMI regularly because I can't get the colors quite right.

But it does make me wonder if the 2408 has this technology somewhere in the processing path. And if so, is this processing done twice, i.e. back to RGB once theG enesis finishes color correction.

Clearly the 2408 has to create RGB data to drive the panel, since LCD panels are RGB devices. Whether that's done by the same chip that converts to YUV and does the mapping I don't know - don't even know for sure if it uses that Genesis chip. But I don't think colour conversion and mapping are likely to cause much lag, because it's just swapping one pixel value for another. It's scaling and sharpening that are processor intensive (and tend to produce artefacts like the ones we're seeing).

When no scaling or sharpening are required i.e. when feeding 1920 x 1200 to the monitor digitally, it should be possible to bypass the processing. If we could, I'm certain most of the issues with the 2408 would go away. 

time for me bench some of the monitor settings. will use my 2005FPW on the DVI, maybe HDMI too. may help to isolate the lag, who knows. i'll to to post anything of interest on this thread tonight.

i agree the scaling would be a significant drag. 

day off today, so I did some benching of 2408WFP versus 2005FPW, full details further below.

my observations:

- different preset modes and sharpness showed no real differences in lag

- defeated sharpness could not be tested, unknown method

- scaling not thoroughly tested (i do not scale), focus was presets

- avg all 2408 DVI testing was 51.25 msec behind the 2005

- avg all 2408 HDMI testing was 19.96 msec behind the 2005

- HDMI via adapter on my configuration was faster, on avg by 31.26 msec

- what the author at monitortest.blogspot.com alluded to, appears to be correct

raw data below, no real use posting pictures somewhere. btw, the (tiny) 2005FPW is back in the box

=========

- both monitors 1680 by 1050, 2005 is filled, 2408 is centered with black bars, ATI h/w scaling off

- numbers are least significant millisecs, format is {2408WFP, 2005FPW, absolute diff}       
- captured with canon xsi ISO 1600 1/2000th sec, all photos dark but very clear       
- ati cat 8.451, all defaults, clone mode, crossfire disabled       
- 2 asus 3870 crossfired using 2 bridges       
- 2408 on DVI with "graphics" setting, custom RGB at {92, 90, 98} with brightness 20 contrast 50

- wide mode 1:1 mappingunles specified

- 2005 on DVI, brightness 100, contrast n/a, sharpness n/a       
- sharpness 50 unless otherwise listed. Varied, not defeated (unknown method)       
- used test from http://www.lagom.nl/lcd-test/ with FF3, no load on machine, Vista64, Q6600@ 3.4, 4GB DDR2 @ 1133       
- any inconclusive pictures dropped       

++++++++++       
on the DVI, both attached primary card on x16       
++++++++++   
Custom RGB preset       
407    454    47
745    823    78
645    692    47
435    497    62
116    179    63
503    550    47
578    640    62
419    465    46
    avg    56.5
Desktop preset       
176    223    47
497    560    63
510    572    62
444    475    31
332    379    47
311    358    47
698    761    63
335    381    46
768    815    47
391    422    31
    avg    48.4
Game preset       
45    93    48
965    996    31
454    501    47
560    607    47
120    183    63
618    680    62
38    84    46
644    676    32
385    432    47
132    195    63
895    942    47
564    611    47
    avg    48.33333333
Mulitmedia preset       
464    510    46
304    351    47
864    927    63
471    518    47
938    984    46
513    560    47
182    229    47
633    680    47
    avg    48.75
sRGB preset       
654    716    62
198    245    47
431    477    46
944    996    52
254    301    47
549    627    78
109    156    47
482    529    47
824    870    46
    avg    52.44444444
Warm preset       
121    184    63
243    305    62
873    920    47
611    673    62
405    452    47
27    90    63
650    696    46
116    163    47
738    785    47
    avg    53.77777778
Custom RGB, sharpness 0       
423    486    63
812    858    46
590    637    47
212    275    63
554    601    47
20    67    47
456    502    46
844    906    62
903    950    47
432    479    47
892    970    78
380    427    47
    avg    53.33333333
Custom RGB, sharpness 100       
265    312    47
308    355    47
227    274    47
887    934    47
547    594    47
372    434    62
119    166    47
586    632    46
581    628    47
328    375    47
    avg    48.4
Custom RGB, sharpness 50, wide mode: fill, DDC/CI disabled       
497    544    47
895    957    62
383    430    47
865    912    47
238    300    62
595    642    47
701    763    62
11    58    47
509    556    47
738    785    47
189    236    47
    avg    51.09090909
       
avg all DVI:        51.22553311
       
++++++++++           
2408 on the HDMI, 2005 on the DVI, both attached primary, ASUS hdmi adapter, CCC sees HDMI       
++++++++++   
Movie preset, wide mode: fill       
408    439    31
704    735    31
885    916    31
313    328    15
556    587    31
837    868    31
484    499    15
765    796    31
61    77    16
389    404    15
    avg    24.7
Game preset, , wide mode: fill       
605    636    31
198    213    15
494    510    16
351    366    15
616    647    31
897    928    31
826    842    16
107    123    16
388    403    15
    avg    20.66666667
Sports preset, , wide mode: fill       
118    134    16
399    414    15
680    695    15
892    923    31
143    174    31
424    455    31
105    121    16
386    402    16
682    698    16
10    26    16
    avg    20.3
Nature preset, , wide mode: fill       
434    450    16
43    58    15
571    587    16
867    883    16
226    242    16
    avg    15.8
Custom RGB preset, wide mode: fill       
403    434    31
684    715    31
965    996    31
292    308    16
21    52    31
302    333    31
582    614    32
946    961    15
242    242    0
554    570    16
    avg    23.4
Custom RGB preset, wide mode 1:1       
776    792    16
57    73    16
338    353    15
650    681    31
522    537    15
803    818    15
83    99    16
767    782    15
47    63    16
422    437    15
    avg    17
Custom RGB preset, wide mode 1:1, sharpness 100       
653    669    16
618    649    31
914    914    0
514    530    16
795    811    16
76    91    15
388    419    31

avg    17.85714286
       
avg all hdmi:    19.96054422
       
hdmi vs dvi:  31.26498889

asus 3870 with supplied dvi-to-hdmi adapter, on the card. then hdmi cable between adapter and 2408.

btw, this hdmi adapter (according to asus) allows digital audio to go over the HDMI, if you connect a digital audio source onto the card (i.e. within the case). i haven't done it, and it should have no impact, but maybe worth mentioning here.

Mike5605,

Was your HDMI hooked up through a DVI->HDMI adapter, or were you using a native HDMI output from your video card straight into the HDMI connector on the 2408?

looked quickly. the sharpness seemed to behave the same as for DVI, i.e. 25 too soft. You may find a difference from DVI if you test HDMI with softMCCS, i.e. 37, 42, 62, etc. These days I leave mine (DVI) at 50. It's not quite the smoothness of the 2005, with the smaller pitch, but I rarely think about it. I'm more of a lag man :smileyindifferent:

not noticed halos (ever) but i haven't really looked for them, only peered very close to the screen (saw nothing). To me, my monitor is as close to perfect as I can ask for, except for the DVI lag.

the HDMI uses a different color space, and I tried earlier to make this look good, but had some black crush problems, but this might be due to inexperience (and color management challenges). I'll be going back in to see if I can get this right, these lag numbers are too compelling.

anandtech used to take them apart. but not for the 2408 review, though. they have a large graphic on the 2005 internals if anyone is interested.

comment per the 2005, "The Genesis gm1501 that acts as the heart of the 2005FPW is clearly visible, and since it is an all inclusive solution, there is no need for other DSPs"

Added: Genesis GM1501 controller spec and functional control block here.