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Old 07-19-08, 11:44 PM   #37
ChrisRay
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Join Date: Mar 2003
Location: Tulsa
Posts: 5,101
Default Re: SLI issues/concerns and stuttering (GTX 200, 8, and 9 Series)

I discussed this over at slizone but there was a real lack of interest. Most people dont seem to notice it. The spikes can and will vary greatly on a numbering amount of factors. Titles. SLI profile and Hex Values,((type of AFR used)) amongst other things.

The test below is not perfect. And it only covers a small portion of the actual benchmark I ran. The lower your "AVG" FPS the higher these inter-frame delay spikes can be. So the higher your FPS. The smaller they will tend to be in my experience. And less noticable. I tend to stick with the philosophy that > 30 FPS with AFR is good.

One important thing to note. A single GPU @ 60 FPS is not comparable framerate to a multi GPU @ 60 FPS. It never will be. Perfect synchronization between inter-frame delay is difficult to achieve without limiting the framerates in some fashion.

Personally. If this problem isnt bothering you. I doubt it ever will. Some people seem far more sensitive to it than others. It should be noted. Single GPUS dont always offer harmonious frame rate distribution either.

Chris

Quote:
Originally Posted by ChrisRay
Theres been alot of questions about frame latency and latency issues in general in regard to AFR recently. So I thought I'd take the time to display them. Ideally you want a "Stable" distribution of frames/latency without any large spikes.

Frame 1 15 MS
Frame 2 30 MS
Frame 3 45 MS
Frame 4 60 MS


Whats bad is seeing things like this.

Frame 1 15 MS
Frame 2 30 MS
Frame 3 80 MS
Frame 4 95 MS



The above would indicate a huge stutter in frame rates. It does not have to be exactly like this. But an even distribution is desired. I did a test with the 9800GX2 with standard AFR2 rendering profiles which is the basis for UT3 rendering in DX 9.0 mode. Recorded the framerates to give you an idea of scaling and then the frame distribution.



1 GPU
Code:
16xAA/16xAF 1680x1050

AVG 34 FPS



Frame, Time (ms)
	1,	 0.000
	2,	27.074
	3,	56.307
	4,	87.132
	5,   116.179
	6,   145.131
	7,   169.784
	8,   204.288
	9,   233.159
   10,   262.923
   11,   292.473
   12,   322.507
   13,   352.017
   14,   381.586
   15,   411.064
   16,   441.138
   17,   467.791
   18,   499.963
   19,   531.042
   20,   559.656
   21,   589.864
   22,   620.279
   23,   650.192
   24,   680.713
   25,   710.491
   26,   740.934
   27,   766.226
   28,   801.618
   29,   831.503
   30,   861.913
   31,   891.762
   32,   921.623
   33,   949.040
   34,   980.577
   35,  1009.604
   36,  1039.672
   37,  1069.171
   38,  1098.195
   39,  1127.361
   40,  1156.043
   41,  1183.926
   42,  1216.107
   43,  1244.913
   44,  1274.907
   45,  1303.598
   46,  1332.216
   47,  1360.964
   48,  1389.595
   49,  1417.806
   50,  1446.821
   51,  1474.548
   52,  1493.034
   53,  1512.845
   54,  1533.250
   55,  1553.810
   56,  1574.784
   57,  1594.828
   58,  1615.219
   59,  1631.470
   60,  1654.473
   61,  1671.612
   62,  1693.719
   63,  1713.170
   64,  1732.179
   65,  1752.094
   66,  1770.919
   67,  1790.117
   68,  1808.289
   69,  1828.003
   70,  1846.868
   71,  1872.386
   72,  1891.147
   73,  1909.331
   74,  1927.426
   75,  1946.287
   76,  1960.520
   77,  1982.130
   78,  2000.099
   79,  2018.241
   80,  2035.320
   81,  2053.132
   82,  2070.958
   83,  2088.296
   84,  2102.113
   85,  2122.730
   86,  2139.770
   87,  2156.561
   88,  2173.863
   89,  2191.406
   90,  2207.880
   91,  2232.666
   92,  2250.956
   93,  2275.716
   94,  2292.520
   95,  2310.522
   96,  2327.861
   97,  2345.959
   98,  2363.320
   99,  2381.670
  100,  2399.386
2 way AFR

Code:
800GX2 2 way AFR

16xAA/16xAF 55 FPS



Frame, Time (ms)
	1,	 0.000
	2,	23.251
	3,	37.420
	4,	58.645
	5,	77.613
	6,	92.450
	7,   114.450
	8,   133.021
	9,   151.792
   10,   167.241
   11,   187.880
   12,   201.923
   13,   223.636
   14,   237.733
   15,   254.805
   16,   276.932
   17,   293.148
   18,   313.911
   19,   334.683
   20,   354.056
   21,   374.022
   22,   392.897
   23,   411.962
   24,   426.175
   25,   443.987
   26,   467.272
   27,   486.385
   28,   506.120
   29,   525.663
   30,   543.978
   31,   562.958
   32,   582.167
   33,   595.963
   34,   617.535
   35,   634.010
   36,   653.931
   37,   667.928
   38,   689.534
   39,   708.618
   40,   722.425
   41,   744.731
   42,   763.371
   43,   782.292
   44,   799.396
   45,   818.075
   46,   831.492
   47,   853.070
   48,   866.957
   49,   882.967
   50,   904.478
   51,   918.501
   52,   934.723
   53,   956.465
   54,   969.880
   55,   986.265
   56,  1003.028
   57,  1026.244
   58,  1046.465
   59,  1063.674
   60,  1081.266
   61,  1094.882
   62,  1110.541
   63,  1131.252
   64,  1148.886
   65,  1166.458
   66,  1184.516
   67,  1197.354
   68,  1218.291
   69,  1233.764
   70,  1247.010
   71,  1267.064
   72,  1284.777
   73,  1297.860
   74,  1318.415
   75,  1336.000
   76,  1353.179
   77,  1369.781
   78,  1387.855
   79,  1404.872
   80,  1421.063
   81,  1437.393
   82,  1454.253
   83,  1466.459
   84,  1484.802
   85,  1500.703
   86,  1513.392
   87,  1530.615
   88,  1546.260
   89,  1561.870
   90,  1573.811
   91,  1592.431
   92,  1607.990
   93,  1623.619
   94,  1639.689
   95,  1652.883
   96,  1669.158
   97,  1684.951
   98,  1696.627
   99,  1713.890
  100,  1729.086
3 way AFR

Code:
16xAA/16xAF 1680x1050

3 Way AFR 9800GX2

68 FPS


Frame, Time (ms)
	1,	 0.000
	2,	14.809
	3,	36.531
	4,	55.247
	5,	74.779
	6,	92.073
	7,   110.632
	8,   129.111
	9,   148.151
   10,   167.451
   11,   186.127
   12,   205.026
   13,   223.613
   14,   243.313
   15,   261.835
   16,   280.535
   17,   299.554
   18,   313.060
   19,   334.218
   20,   352.834
   21,   367.311
   22,   388.577
   23,   408.769
   24,   427.858
   25,   446.820
   26,   465.476
   27,   484.188
   28,   503.180
   29,   521.546
   30,   539.992
   31,   559.189
   32,   577.431
   33,   595.868
   34,   614.422
   35,   628.173
   36,   649.512
   37,   668.124
   38,   686.428
   39,   705.360
   40,   724.033
   41,   742.462
   42,   755.776
   43,   778.337
   44,   796.825
   45,   815.875
   46,   834.967
   47,   853.475
   48,   871.421
   49,   884.958
   50,   906.506
   51,   940.048
   52,   959.902
   53,   980.526
   54,  1000.534
   55,  1019.928
   56,  1034.381
   57,  1050.408
   58,  1071.971
   59,  1089.898
   60,  1108.124
   61,  1125.227
   62,  1142.622
   63,  1160.161
   64,  1173.424
   65,  1194.519
   66,  1211.533
   67,  1228.452
   68,  1240.837
   69,  1261.165
   70,  1278.234
   71,  1295.251
   72,  1308.040
   73,  1327.572
   74,  1344.743
   75,  1361.489
   76,  1378.773
   77,  1395.295
   78,  1411.521
   79,  1427.697
   80,  1441.494
   81,  1458.748
   82,  1474.552
   83,  1490.709
   84,  1506.731
   85,  1523.046
   86,  1538.790
   87,  1555.225
   88,  1571.991
   89,  1583.962
   90,  1598.445
   91,  1616.243
   92,  1631.849
   93,  1647.193
   94,  1662.706
   95,  1678.221
   96,  1693.423
   97,  1708.451
   98,  1722.795
   99,  1737.503
  100,  1752.506
4 way AFR

Code:
16xAA/16xAF 1680x1050

76 FPS

9800GX2 4 way AFR.



Frame, Time (ms)
	1,	 0.000
	2,	17.615
	3,	38.653
	4,	56.662
	5,	71.880
	6,	87.698
	7,   109.398
	8,   123.345
	9,   139.849
   10,   156.585
   11,   173.332
   12,   194.883
   13,   213.259
   14,   226.749
   15,   243.810
   16,   266.096
   17,   284.397
   18,   302.953
   19,   321.641
   20,   340.009
   21,   353.346
   22,   375.211
   23,   393.943
   24,   411.867
   25,   425.231
   26,   447.935
   27,   466.789
   28,   482.066
   29,   496.718
   30,   512.705
   31,   533.635
   32,   551.839
   33,   569.545
   34,   587.134
   35,   599.860
   36,   616.424
   37,   636.653
   38,   654.724
   39,   673.927
   40,   694.781
   41,   712.353
   42,   729.735
   43,   742.743
   44,   764.688
   45,   777.433
   46,   793.458
   47,   808.783
   48,   829.520
   49,   847.586
   50,   865.191
   51,   877.281
   52,   893.493
   53,   913.825
   54,   931.091
   55,   948.839
   56,   966.513
   57,   984.168
   58,  1001.494
   59,  1014.018
   60,  1029.752
   61,  1050.008
   62,  1067.161
   63,  1084.260
   64,  1101.465
   65,  1118.299
   66,  1134.620
   67,  1151.449
   68,  1163.192
   69,  1178.216
   70,  1193.166
   71,  1211.795
   72,  1227.911
   73,  1244.068
   74,  1255.835
   75,  1270.442
   76,  1288.367
   77,  1303.010
   78,  1319.538
   79,  1334.829
   80,  1350.347
   81,  1369.091
   82,  1386.848
   83,  1402.680
   84,  1418.351
   85,  1429.626
   86,  1444.093
   87,  1461.741
   88,  1477.116
   89,  1492.554
   90,  1507.896
   91,  1519.476
   92,  1536.565
   93,  1551.513
   94,  1566.242
   95,  1580.087
   96,  1593.914
   97,  1608.435
   98,  1622.754
   99,  1636.617
  100,  1650.884
Let me know if you have any questions..
__________________
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