Abstract: A process and implementing system is provided for conducting a memory test for isolating and identifying failed cache memory modules in a memory subsystem of a computer system. The methodology initially selects 303 a block of memory which is twice the size of the cache 105 being tested. The cache 105 is then disabled 305 and a first test is performed 307 on the selected block of to isolate byte addresses of individual bit failures. If bit failures are detected 308, the appropriate byte address is mapped 310 and the test is ended 321. If no bit errors are detected in the first test, the cache is enabled 309 and a second test is performed and the block is tested 311 for failures. Any detected failures are assumed to be cache failures and the appropriate byte address is mapped 315. The cache is again disabled 317. An appropriate message is then displayed 319 to indicate the results of the testing.