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VCP-DCV vSphere Performance and Scaling Practice Question

Which THREE techniques are recommended to improve virtual machine network performance in a vSphere environment? (Select three.)

⚠ Common exam trap

VCP-DCV often tests the misconception that more virtual switches or emulated adapters improve performance, when in fact paravirtualized adapters and hardware offloads like SR-IOV are the recommended techniques.

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

✓

Enable Jumbo Frames on the virtual switch.

Option A is correct because enabling Jumbo Frames (MTU 9000) on the virtual switch, physical uplinks, and guest OS reduces per-packet overhead and CPU utilization, improving throughput for large data transfers. Option B is correct because the VMXNET3 adapter is a paravirtualized NIC designed for vSphere that delivers higher throughput and lower CPU utilization than emulated adapters like e1000e. Option E is correct because SR-IOV on supported NICs allows a virtual function to be passed directly to the VM, bypassing the hypervisor's virtual switch datapath for near-native network performance and reduced latency. Option C is not recommended because dedicating a separate virtual switch per VM adds management overhead and does not inherently improve performance; standard vSwitch design uses shared switches with proper uplink and teaming configuration. Option D is incorrect because e1000e is an emulated Intel adapter that offers lower performance and higher CPU overhead than VMXNET3.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

✓
Enable Jumbo Frames on the virtual switch.
Why this is correct
Enabling jumbo frames raises the MTU to 9000 on the virtual switch, reducing per-packet header overhead and CPU interrupts for large, sequential transfers. This satisfies the stem's performance-improvement constraint, provided every device along the path—physical switch, uplinks and guest NICs—is configured identically, otherwise fragmentation degrades throughput.
✓
Use the VMXNET3 virtual network adapter.
Why this is correct
VMXNET3 is a paravirtualised adapter designed for vSphere, bypassing the emulation overhead that E1000 incurs. It delivers lower CPU utilisation, higher throughput and full offload support (TSO, LRO, RSS), directly satisfying the stem's requirement to improve virtual machine network performance.
✗
Use a dedicated virtual switch for each VM.
Why it's wrong here
A dedicated virtual switch per VM multiplies management overhead and does not increase throughput; performance comes from NIC teaming, VMXNET3 adapters, jumbo frames and traffic separation. Isolation via separate switches is genuinely correct for security or multi-tenant segmentation, which is why it appears plausible here.
✗
Use the e1000e network adapter type.
Why it's wrong here
The e1000e emulates an Intel 82574L and lacks the paravirtualised datapath, so it delivers lower throughput and higher CPU cost than VMXNET3. It is tempting because e1000e works out of the box on guests lacking VMware Tools, which is the scenario where it would be the right pick.
✓
Enable SR-IOV on supported NICs.
Why this is correct
SR-IOV bypasses the software virtual switch by presenting virtual functions directly to the guest, cutting CPU overhead and latency on the data path. For workloads needing maximum throughput on supported NICs, this hardware-assisted passthrough satisfies the stem's performance-improvement constraint.

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VCP-DCV vSphere Performance and Scaling Practice Question

Why each option matters

Option-by-option breakdown

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