Users Cry Foul After AMD Stripped Memory Crypto From Its Consumer CPUs
Published on 2026-06-15T20:02:00Z
An anonymous reader quotes a report from Ars Technica: A decade ago, AMD added a protection to its high-end CPUs to protect them against cold boot attacks and other types of physical exploits that siphon sensitive data out of the connected memory chips. Short for Transparent Secure Memory Encryption, TSME encrypts the entire contents stored in memory, making the data useless to physical attackers. Over time, AMD added TSME to lower-end processors, including the consumer version of its Ryzen chips, a CPU that costs less than the Pro version. Over the years, users of these lower-end chips have gotten used to the added security. Recently and without warning or notice, this lower-end line of AMD chips suddenly dropped the protection, and did so in a way that was impossible to detect on Windows machines and required a fair amount of technical work when using Linux. AMD has yet to say why TSME worked on these CPUs, or even to confirm the change. AMD declined to answer questions sent by email other than to say TSME "is a security feature only applied to PRO CPUs as part of AMD PRO Technologies." The statement is the first known time the chipmaker has explicitly made this restriction public. [...] There's no indication that AMD ever advertised or marketed TSME as being available in consumer CPUs. AMD has long said that a related memory protection, Secure Memory Encryption (SME), is available only in the Pro and Epyc CPU tiers. SME is OS-managed. It uses a single key and allows the OS to selectively encrypt individual memory pages. TSME is firmware-managed. It encrypts all RAM with no OS involvement. When active, it provides protection against physical attacks, including cold boot exploits, DRAM interface snooping, and memory module removal. It activates silently when enabled in the BIOS, making it the more practically useful of the two protections. Ben Kilpatrick, a self-described "privacy-conscious Linux hobbyist," discovered that TSME had stopped working on his consumer Ryzen processor despite remaining enabled in the BIOS. He spent months investigating, persuaded MSI engineers to test multiple CPUs, motherboards, and firmware versions, and filed a public AMD bug report that traced the change to newer AGESA firmware apparently disabling TSME on consumer chips while retaining it on Pro and EPYC models. "AMD engineers' comments, such as those mentioned above, and the years of TSME working just fine in the lower-cost tier processors, have understandably conditioned Kilpatrick and other users to reasonably regard it as an expected part of the chip package," reports Ars Technica. "AMD quietly removing it and providing no acknowledgment or explanation strikes these users as something of a betrayal." Joe Fitzgerald, an expert in silicon-level security, said in an interview: "They could have not realized they did it leading to their cagey responses, or they could have done it intentionally and tried to get away with it, leading to the same cagey responses. But I really feel like an explanation should be in order, even if it was 'TSME was never supposed to be supported. We did ship some firmwares that erroneously enabled it, but you shouldn't use them since we can't guarantee it'll work properly.'"
Published on 2026-06-15T20:02:00Z
An anonymous reader quotes a report from Ars Technica: A decade ago, AMD added a protection to its high-end CPUs to protect them against cold boot attacks and other types of physical exploits that siphon sensitive data out of the connected memory chips. Short for Transparent Secure Memory Encryption, TSME encrypts the entire contents stored in memory, making the data useless to physical attackers. Over time, AMD added TSME to lower-end processors, including the consumer version of its Ryzen chips, a CPU that costs less than the Pro version. Over the years, users of these lower-end chips have gotten used to the added security. Recently and without warning or notice, this lower-end line of AMD chips suddenly dropped the protection, and did so in a way that was impossible to detect on Windows machines and required a fair amount of technical work when using Linux. AMD has yet to say why TSME worked on these CPUs, or even to confirm the change. AMD declined to answer questions sent by email other than to say TSME "is a security feature only applied to PRO CPUs as part of AMD PRO Technologies." The statement is the first known time the chipmaker has explicitly made this restriction public. [...] There's no indication that AMD ever advertised or marketed TSME as being available in consumer CPUs. AMD has long said that a related memory protection, Secure Memory Encryption (SME), is available only in the Pro and Epyc CPU tiers. SME is OS-managed. It uses a single key and allows the OS to selectively encrypt individual memory pages. TSME is firmware-managed. It encrypts all RAM with no OS involvement. When active, it provides protection against physical attacks, including cold boot exploits, DRAM interface snooping, and memory module removal. It activates silently when enabled in the BIOS, making it the more practically useful of the two protections. Ben Kilpatrick, a self-described "privacy-conscious Linux hobbyist," discovered that TSME had stopped working on his consumer Ryzen processor despite remaining enabled in the BIOS. He spent months investigating, persuaded MSI engineers to test multiple CPUs, motherboards, and firmware versions, and filed a public AMD bug report that traced the change to newer AGESA firmware apparently disabling TSME on consumer chips while retaining it on Pro and EPYC models. "AMD engineers' comments, such as those mentioned above, and the years of TSME working just fine in the lower-cost tier processors, have understandably conditioned Kilpatrick and other users to reasonably regard it as an expected part of the chip package," reports Ars Technica. "AMD quietly removing it and providing no acknowledgment or explanation strikes these users as something of a betrayal." Joe Fitzgerald, an expert in silicon-level security, said in an interview: "They could have not realized they did it leading to their cagey responses, or they could have done it intentionally and tried to get away with it, leading to the same cagey responses. But I really feel like an explanation should be in order, even if it was 'TSME was never supposed to be supported. We did ship some firmwares that erroneously enabled it, but you shouldn't use them since we can't guarantee it'll work properly.'"
Read more of this story at Slashdot.
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