PVU vs VPC vs RVU: which metric applies to your product.
IBM licenses different products by different metrics, and confusing them is a fast way to count your estate wrong. PVU ties cost to processor capacity, RVU ties it to a resource quantity, and VPC ties it to virtual cores under the modern sub-capacity rules.
Before you can reconcile a single product against its entitlement, you have to know what unit it is sold in. IBM uses several metrics that sound interchangeable and are not. Counting a PVU product as though it were an RVU product, or assuming an old PVU position still holds when the product moved to VPC, produces numbers that an auditor will happily correct in IBM's favor.
PVU is about processor capacity
The Processor Value Unit is a core based metric. Each core carries a PVU rating that depends on the processor type, with a common Intel core rated at roughly 70 PVU, and your requirement is that rating multiplied by the cores allocated to the IBM software. PVU ties the cost directly to hardware capacity, which is exactly why sub-capacity licensing and ILMT matter so much for PVU products: without continuous measurement you are charged for every physical core rather than the virtual cores actually in use.
RVU is about a resource quantity
The Resource Value Unit is usage based rather than processor based. It ties the license to a quantity of some resource the product manages, such as client devices, managed users, or another counted entity defined in the product documentation. RVU has nothing to do with CPU, so the defensive questions are entirely different: not how many cores are allocated, but how the resource is defined, what counts toward it, and whether the count is being measured correctly.
- PVU: cores allocated times the per core PVU rating, capacity based
- RVU: a counted resource quantity such as devices or managed users, usage based
- VPC: virtual processor cores under sub-capacity, with ILMT now required
VPC and the modern sub-capacity rules
The Virtual Processor Core metric is where many estates are out of date. Since Passport Advantage version 11, which applied to existing customers from May 1 2023, sub-capacity reporting and ILMT apply to VPC metered products as well, and manual counting is no longer permitted. A team that still counts a Cloud Pak or a VPC product by hand because that is how it was done years ago is carrying an undocumented position that the current rules do not support.
Reading the metric off the entitlement
The authoritative source for which metric governs a product is the License Information document and your Passport Advantage entitlements, not memory or vendor conversation. The same product family can be sold under different metrics across versions and editions, so the metric has to be confirmed per entitlement. Getting this right is the precondition for every other calculation, because the metric determines what you count and how IBM will check it.
The metric is the first thing an audit fixes if you have it wrong. PVU is capacity, RVU is a resource quantity, VPC is virtual cores under the current sub-capacity rules, and confirming the right metric per entitlement is the precondition for a defensible count of any IBM product.
Not certain which metric governs each product?
Our PVU Reconciliation engagement confirms the governing metric for every entitlement and recalculates your position independently against Passport Advantage records before IBM does.
See PVU Reconciliation →The IBM Audit Brief
Audit triggers, ILMT pitfalls, and settlement tactics for IBM software buyers.
Independent, buyer side IBM software audit defense and negotiation. Not affiliated with IBM Corporation.