Testprogramm für AMD-Prozessoren
 
Nachdem AMD eingeräumt hatte, dass "eine Handvoll" Prozessoren (Athlon, Duron, sowie auch K6-xx) fehlerhaft durch den Endtest geschlüpft war, hat c't nun die mögliche Fehlerquelle aufgespürt und ein kleines Testprogramm entwickelt. Die Ursache für die falschen Pixel bei JPEG-Bildern oder bei der Darstellung vom MPEG-Videos liegt in einem so genannten "speedpath" im MMX-Teil des Prozessors. Insbesondere die MMX-Multiplikation zeigte sich davon betroffen. Das ergab die Analyse eines von einem c't-Leser eingeschickten, defekten Duron-Prozessors.  
 
Das Programm pmultest überprüft nun mit Zufallszahlen eine Vielzahl von Multiplikationen der drei MMX-Befehle pmullw, pmulhw, pmulhuw und listet die Zahl der Fehler auf. Wer einen fehlerhaften AMD-Prozessor findet, kann sich an die AMD-Hotline (089/450-53199) wenden und den Prozessor umtauschen ? und möge bitte auch die c't-Redaktion benachrichtigen. (as/c't)
 

Programme test pour des AMD-Prozessoren  
 
Après qu'AMD avait accordé qu'"une poignée" avait glissé défectueux à des transformateurs (Athlon, Duron, ainsi qu'également K6-xx) par l'essai final, a c't maintenant la source d'erreurs possible cherché et un petit programme test développé. La cause pour les faux pixels avec des JPEG-Bildern ou lors de la représentation du MPEG-Videos se trouve dans un si cité "speedpath" dans le MMX-Teil du transformateur. En particulier le MMX-Multiplikation a paru concerné. * cela donner le l'analyse un von un c't-Leser retourner, défectif Duron-Prozessors.
 
Le programme pmultest réexamine maintenant avec des nombres aléatoires une multiplicité de multiplications des trois MMX-Befehle pmullw, pmulhw, pmulhuw et énumère le nombre des erreurs. * celui qui un défectueux AMD-Prozessor trouver, pouvoir lui-même le AMD-Hotline (089/450-53199) tourner et le transformateur échanger - et pouvoir s'il vous plaît aussi qui c't-Redaktion informer. ( as /c't)

AMD-K6®-2, Athlon, and Duron
JPEG Display Problem
DIAGNOSTIC PROCEDURE:
Software Diagnostic Test: In August 2001, Andreas Stiller in Germany, produced a small program in C that tests the MMX instructions pmullw, pmulhw, and pmulhuw. It is these instructions that AMD's tests failed to thoroughly evaluate. Mr. Stiller's program provides a direct way of testing your AMD processor for this JPEG Display Problem. It is provided here (pmultest.zip, 25 Kbytes) for your convenience. The use of his test program largely eliminates the need to follow the indirect diagnostic tests that are outlined below. (This program was first described at Heise Online.)
 
The series of diagnostic tests outlined documented below serve to indirectly eliminate possible software causes for the problem you may be experiencing. If the problem persists, it is very likely that your AMD-K6-2 microprocessor is flawed. You should be sure to run Mr. Stiller's program to evaluate your CPU chip. It is assumed that your computer system does not exhibit problems other than the specific JPEG image distortion problem described in this report. Your system should, for example, display GIF images properly. There should be no problems indicated by ! or x when you review the list of devices shown on the Device Manger tab by the System applet in the Control Panel.
 
Begin by saving a copy of the test JPEG image file (test.jpg) on your computer?s local disk drive. Right-mouse-button click on this link and select Save Target As...  
 
After you have a local copy of this file, you can test your system by viewing this JPEG image using Microsoft Internet Explorer V4 without having to be connected to the Internet. To view the local copy of this test image using Microsoft Internet Explorer, select File, Open? from the menu. Click the Browse button on the Open dialog box and navigate to the folder in which you?ve saved the test.jpg image file. Select "Files of type: JPEG Files" and then select the test.jpg image file. Click the Open button then OK to view the file. Verify that you can reproduce the problem using the test.jpg image file.
 
Diagnostic Test 1: This first test turns off graphics hardware acceleration, by disabling this functionality through your display driver. Click Start and select Settings, Control Panel. Double-click the System applet. Select the Performance tab and click the Graphics? button in the Advanced settings panel. Move the Hardware acceleration slider all the way to the left to the setting "None." Click OK and Close and restart your computer when you are prompted to do so.  
 
After restarting, view the test.jpg image using Microsoft Internet Explorer. If the problem no longer occurs, the problem was caused by a software problem with the advanced hardware acceleration functions supported by your video display driver. You may continue to operate your computer with this setting. You should obtain an updated and corrected video display driver from the vendor when one becomes available.
 
If the problem persists, continue with Diagnostic Test 2.
 
Diagnostic Test 2: This second test eliminates potential software problems that may be caused by your display driver. Click Start and select Settings, Control Panel. Double-click the Display applet. Select the Settings tab and click the Advanced? button. Select the Adapter tab and click the Change? button. Use the Update Device Driver Wizard to change your display device driver to the Microsoft "Standard Display Adapter (VGA)." Follow these steps. In the second step of the Wizard, select "Display a list of all the drivers in a specific location?" In the next step, select the option "Show all hardware." Under Manufacturers, select "(standard display types)" and under Models select "Standard Display Adapter (VGA)." Complete the remaining steps to Finish the Wizard and restart your computer when you are prompted to do so.  
 
After restarting, view the test.jpg image using Microsoft Internet Explorer. If the problem no longer occurs, the problem was caused by a basic software problem with your video display driver. You should obtain an updated and corrected video display driver from the vendor when one becomes available.
 
If the problem persists, you should continue with Diagnostic Test 3.
 
Diagnostic Test 3: This third test attempts to eliminate possible software conflicts that could cause this type of problem. Restart your computer without processing the software items that are loaded by your config.sys, autoexec.bat, win.ini, and system.ini files as your computer starts up. If you are running Microsoft Windows 98, this may be done by selecting Start, Run? and running MSCONFIG.EXE. When the System Configuration Utility dialog box is displayed, select the General tab. Select the option Selective startup and clear each of the checkboxes. Click OK and restart your computer.
 
After restarting, view the test.jpg image using Microsoft Internet Explorer. If the problem no longer occurs, the problem was caused by a software item that was loaded during startup. Further troubleshooting will be required to identify the specific software item causing the difficulty. Please refer to the Microsoft Knowledge Base for further information.
 
If the problem persists, it is very likely that this problem is caused by a defect in your AMD-K6-2 microprocessor chip.  
 
Diagnostic Test 4: If the above tests do not eliminate the problem, you may further confirm that your system contains a flawed AMD-K6-2 microprocessor by viewing the test JPEG image using another application that is known to be unaffected by this problem. The JPEG image should be displayed correctly when Netscape Navigator, Microsoft Photo Editor, or Micrografx Picture Publisher are used.
 
The most direct test for this specific problem is the use of Mr. Andreas Stiller's program, described at the top of this page.
 
To correct the problem you must return the chip or the computer to the vendor from which it was purchased for a warrantee exchange. If you purchased a complete computer system, do not remove the AMD-K6-2 microprocessor, since doing so may void your system warrantee.
 
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