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AMD-K6®-2, Athlon, or Duron
JPEG Display Problem
PROBLEMS:
JPEG Images are Distorted when Displayed by Microsoft Internet Explorer V4 or V5
JPEG Images are Distorted when Embedded within Microsoft Office 97 or Office 2000 Documents
When the Microsoft Windows Active Desktop is Viewed As a Web Page, JPEG Images Appearing on the Desktop are Distorted
When MPEG Video Clips are Played, "Static" Appears Within the Video, Static and Pops are Heard in the Audio
Some Video Games that Utilize DirectX Display Random Spots and Noise or "Hiss" is Heard in the Audio
The information in this article applies to:
AMD-K6-2, Athlon, and Duron Microprocessors
Joint Photographic Experts Group (JPEG or .jpg) images
MPEG Video and Audio
DirectX
Microsoft Internet Explorer V4 and V5 (with any updates and Service Packs)
Microsoft Windows 95, Windows 98, Windows ME, Windows NT V5, Windows 2000
Microsoft Office 97 and Office 2000 Applications
Additional Keywords: Win95, Win98, WinME, WinNT, Win2000, MSIE, MSIE4, MSIE5, Office97, Office2000, 3DNow!
SYNOPSIS:
Some AMD-K6®-2, Athlon, and Duron microprocessors cause JPEG images to be incorrectly displayed in some applications. When you view a Web page containing a Joint Photographic Experts Group (JPEG or .jpg) image file in Microsoft Internet Explorer V4 or V5, the image appears distorted. Although the image size and position is correct, most of the pixels are displayed using incorrect colors. This problem is also seen when you use a JPEG image in an Office 97or Office 2000 document. When the option to view the Microsoft Windows Active Desktop as a Web Page is selected, JPEG images appearing on the Active Desktop are also distorted.
Even on computers that have such an AMD microprocessor with this defect, JPEG image files are correctly displayed using other applications, including Microsoft Internet Explorer V3, Microsoft Photo Editor and Netscape Navigator.
A test, that requires the use Microsoft Internet Explorer V4 or V5, is provided below. A software diagnostic procedure is also given to aid in eliminating other problems that may cause problems that exhibit similar symptoms.
This problem does not affect other image formats like Graphic Interchange Format (GIF) image files.
DISCUSSION:
Some AMD-K6-2, Athlon, and Duron microprocessor chips are evidently slightly flawed. These flawed chips execute most all sequences of computer instructions properly and the vast majority of applications operate properly. However, the algorithm used by a few applications to decode and display JPEG compressed image files does not yield the correct results on some AMD microprocessors. The algorithm used by Microsoft Internet Explorer V4, V5, or Office 97 or Office 2000 applications, like Word, include a sequence of instructions that does not yield the correct results when executed on such a flawed AMD microprocessor. In these applications, JPEG images are distorted when they are displayed or when they are saved in another file format. In addition, JPEG images that are displayed when you view your Active Desktop as a Web page are also distorted.
MPEG video is also adversely affected when played back. Video games that utilize DirectX display random dots on the screen, and noise or "hiss" is heard in the audio.
This problem has been observed with both PCI and AGP video cards and a variety of display drivers, including the standard Microsoft VGA driver. The problem is not present in all AMD-K6-2, Athlon, or Duron microprocessor chips. Replacing the processor chip resolves the problem.
Many applications use slightly different algorithms or instruction sequences to decode and display JPEG image files. As a result, those applications will not exhibit the problem even on computers that incorporate such a flawed AMD microprocessor. Netscape Navigator, Microsoft Internet Explorer V3, Micrographx Picture Publisher, and Microsoft Photo Editor are examples of applications that never exhibit this problem. JPEG images will always be correctly displayed by these programs!
Other types of images, like Graphics Interchange Format (GIF or .gif) image files are never affected.
Not all AMD-K6-2, Athlon, or Duron microprocessors exhibit this behavior. The great majority of AMD microprocessors operate correctly. On AMD microprocessors that exhibit this problem, the degree of distortion is reduced when the microprocessor clock rate is reduced.
This defect has been observed in only a small proportion of AMD microprocessors. The majority of AMD microprocessors operate correctly.
This problem has not been observed on any microprocessors manufactured by Intel or Cyrix.
Test Your AMD-K6-2 Microprocessor
If you are viewing this Web page using Microsoft Internet Explorer V4 or V5 and your computer uses an AMD-K6-2, Athlon, or Duron microprocessor that is flawed in this manner, the problem will be evident when you view the test JPEG image shown on the left. (This JPEG image is displayed properly, even on computers with a flawed AMD microprocessor, when Netscape Navigator is used.)
The image to the right is an equivalent image in GIF format. It always appears correctly and shows how the test JPEG image should appear. On a properly running AMD microprocessor, the JPEG image above left and this GIF image to the right will appear identical.
If both of the images above appear identical when viewed with Microsoft Internet Explorer V4 or V5, then your AMD microprocessor does not have this problem! If you would like to see an example image that shows the distortion that does occur on computers that use a flawed AMD microprocessor, click here.
On an AMD microprocessor that has this flaw, the amount of distortion that occurs when displaying a JPEG image is reduced when the clock rate to the microprocessor is reduced. The two GIF images below document the results that are obtained when a flawed AMD-K6-2 300 MHz microprocessor is operated at 266 MHz and at 300 MHz:
Result at 266 MHz Result at 300 MHz
This problem does not appear to be caused by a fundamental design flaw with the AMD-K6-2 microprocessor, and the vast majority of these microprocessors operate properly. Evidently, certain sequences of instructions on some AMD-K6-2 microprocessors do not yield the correct results at the rated speed. It is strongly suspected that algorithms that have been optimized to use the MMX instructions may be prone to this type of failure on AMD microprocessors with this flaw. The failure may also be data dependant, since some portions of the JPEG image are displayed properly, while other portions of the image are incorrectly decoded.
This problem has been reported by others, using other types of motherboards and other types of video adapters, including both AGP as well as PCI video cards. Different versions of the manufacturer's video drivers and BIOS software have been used without having any effect on this problem. The problem continues to occur when the Microsoft Standard VGA display driver is used. In all cases, the AMD microprocessor is considered to be the root cause, since replacing only the microprocessor chip corrects this problem.
DIAGNOSIS:
It is important to recognize that similar display problems are often caused by software problems, rather than a microprocessor problem. Frequently, a problem with the display adapter's driver or a software conflict may cause similar difficulties. An IRQ or DMA conflict or a problem with the display adapter card or firmware can also present similar problems.
The most conclusive way to diagnose this problem is to exchange the AMD microprocessor chip from a computer that exhibits this problem with the same speed and type of AMD microprocessor from another computer that operates properly. If the problem moves from one computer to the other, you may confidently conclude that the microprocessor chip itself is flawed. To correct the problem you must return the microprocessor chip or the computer to the vendor from which it was purchased for a warrantee exchange.
Currently available diagnostic utilities, like American Megatrends’ AMIDiag V5.42A, do not detect this defect in the AMD microprocessor.
Since it is often very inconvenient or impractical to exchange a microprocessor that you suspect is defective with a known good AMD microprocessor, you may follow our Software Diagnostic Procedure to better evaluate if a potential microprocessor problem is causing your problem.
Further Information:
This problem was present on our family's computer, and after trying to resolve this with alternative video adapters, display drivers, later BIOS versions, and various Windows updates, it was finally resolved by replacing just the AMD-K6-2 microprocessor. The information published here is based on our experience and that of others who have also had this type of problem.
After publishing this information on the Internet via these Web pages, we've received email from several additional individuals from around the world who have also experienced this same problem and were able to correct it by simply exchanging their AMD-K6-2 microprocessor with another one. Reports from other PC enthusiasts confirm that this problem also occurs with some AMD-K6-2 300 and 350 MHz microprocessors as well as some 700 and 800 MHz Athlon and 600 and 700 MHz Duron microprocessors.
Our flawed AMD K-6-2 microprocessor was returned to AMD for further analysis. The metal lid on our original flawed microprocessor is silk-screened with the Revision and Date Code "A 9825GPEW".
AMD provided a replacement microprocessor. The replacement microprocessor corrected the problem. No changes were made to any of the other hardware or software on our PC.
The support engineer at AMD later reported to us that they had been able to reproduce the problem using our chip. Surprisingly, AMD continues to tell people that they have not heard of this problem, even though this problem has been documented here since October 1998! The Case number assigned for our problem at AMD in 1998 was Case #65398. The support engineer who worked with us and provided us with the replacement microprocessor chip was Mr. Adrian Brooks.
This problem has been discussed in the Newsgroup microsoft.public.inetexplorer.ie4 in August and September 1998. You may also wish to contact AMD Technical Support to report a problem that you are having. In the US, you can reach AMD Technical Support at (408) 749-3060. However, please be aware that as recently as December 2000, AMD continues to deny this problem. Fortunately, they have provided replacement microprocessors to several individuals who have reported this problem, and this has corrected the problem.
To assist us to help you better, we'd like to know if the information in this article was useful to you. To communicate with the author, please send email to AMDProblem@GordonFamily.com. We'd like to hear from you if replacing your AMD microprocessor has resolved this problem, or if you have additional information regarding this issue. |
