What Technology Change Enables 1 Terabyte (TB) Enclave Page Cache (EPC) Size in Intel® Xeon® Scalable Processor Platforms?

• The maximum EPC size for Intel® Software Guard Extensions (Intel® SGX) processors before 3rd Gen Intel® Xeon® Scalable Processor platforms was 256 MB.
• Unable to determine which technology enables 1 TB of EPC on Intel® Xeon® Scalable Processor platforms.

Enclave Page Cache (EPC) is a technology available on Intel® Xeon® Scalable Processors. Depending on the generation and processor SKU, the EPC will be set. 

• 3rd Generation Intel® Xeon® Scalable Processors support 512 GB of EPC size, which adds up to 1 TB on a two-socket platform.
• 4th Gen Intel® Xeon® Scalable Processors, some SKUs support 512GB of EPC size, while other SKUs only supports 128GB of EPC size. 
• 5th Gen Intel® Xeon® Scalable Processors,we have 3 options, SKUs supporting 512GB of EPC size, SKUs supporting 128GB of EPC size and SKUs supporting 64GB of EPC size.
• Intel® Xeon® 6 supports 512 GB of EPC size, which adds up to 1 TB on a two-socket platform.
• Intel® SGX switched from using the Memory Encryption Engine (MEE), which uses on-die space for a Merkle Tree that doesn’t expand easily, to using Advanced Encryption Standard - XEX Tweakable Block Cipher with Ciphertext Stealing (AES-XTS), enabling a larger EPC.

For a detailed specification, visit Intel® Product Specifications - Intel® Xeon® Processors.