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Sure, but the PPE was "just" an iteration on their existing PowerPC core line - that wasn't really the focus of the "unique" Cell changes in the first place. I

by kimixa 2y ago

Sure, but the PPE was "just" an iteration on their existing PowerPC core line - that wasn't really the focus of the "unique" Cell changes in the first place. If they just asked for a 3-core SMP version of a PowerPC and the Cell project never existed, I suggest it's likely it would still look very similar to what was released in the xbox. VMX already existed, POWER5 already had SMT. I don't see there being a huge amount of new technology made for the Cell's PPE for the Xbox project to import in the first place.

sillywalk 2y ago
> Sure, but the PPE was "just" an iteration on their existing PowerPC core line I'm pretty sure the PPE was an entirely new core design. It used the PowerPC ISA and had features similar to earlier designs, but it was new. From [0]: "although the central processor is based on IBM's PowerPC architecture, it's a new design, not an existing PowerPC core. Cell's central processor is similar to the current PowerPC 970 chip, although it's not an exact match. " > If they just asked for a 3-core SMP version of a PowerPC and the Cell project never existed, I suggest it's likely it would still look very similar to what was released in the xbox. VMX already existed, POWER5 already had SMT. I don't think at the time IBM had anything else that Microsoft could've used. It's PowerPC 7xx wouldn't have been an improvement (or not enough of one) over the Pentium 3 in the original X-Box. The PowerPC 970 was hot / power hungry - the dual-core models that Apple used requiring liquid cooling and weren't out until 2005. The POWER5 with SMT was in development, but it was designed for IBM's servers and existing customer workloads. I don't know if it could've modified it to add another core, plus the VMX128 stuff that Microsoft needed, if IBM would've been willing to do that, or if that chip would've been too expensive for a console. [0] https://www.embedded.com/a-glimpse-inside-the-cell-processor/ https://www.embedded.com/a-glimpse-inside-the-cell-processor...

by kimixa 2y ago

sillywalk 2y ago

> Sure, but the PPE was "just" an iteration on their existing PowerPC core line I'm pretty sure the PPE was an entirely new core design. It used the PowerPC ISA and had features similar to earlier designs, but it was new. From [0]: "although the central processor is based on IBM's PowerPC architecture, it's a new design, not an existing PowerPC core. Cell's central processor is similar to the current PowerPC 970 chip, although it's not an exact match. " > If they just asked for a 3-core SMP version of a PowerPC and the Cell project never existed, I suggest it's likely it would still look very similar to what was released in the xbox. VMX already existed, POWER5 already had SMT. I don't think at the time IBM had anything else that Microsoft could've used. It's PowerPC 7xx wouldn't have been an improvement (or not enough of one) over the Pentium 3 in the original X-Box. The PowerPC 970 was hot / power hungry - the dual-core models that Apple used requiring liquid cooling and weren't out until 2005. The POWER5 with SMT was in development, but it was designed for IBM's servers and existing customer workloads. I don't know if it could've modified it to add another core, plus the VMX128 stuff that Microsoft needed, if IBM would've been willing to do that, or if that chip would've been too expensive for a console. [0] https://www.embedded.com/a-glimpse-inside-the-cell-processor/ https://www.embedded.com/a-glimpse-inside-the-cell-processor...