diff --git a/renderdoc/driver/vulkan/vk_common.cpp b/renderdoc/driver/vulkan/vk_common.cpp
index 07201c9f0..608c563da 100644
--- a/renderdoc/driver/vulkan/vk_common.cpp
+++ b/renderdoc/driver/vulkan/vk_common.cpp
@@ -134,10 +134,13 @@ void GPUBuffer::Create(WrappedVulkan *driver, VkDevice dev, VkDeviceSize size, u
 
   align = (VkDeviceSize)driver->GetDeviceProps().limits.minUniformBufferOffsetAlignment;
 
+  // for simplicity, consider the non-coherent atom size also an alignment requirement
+  align = AlignUp(align, driver->GetDeviceProps().limits.nonCoherentAtomSize);
+
   sz = size;
   // offset must be aligned, so ensure we have at least ringSize
   // copies accounting for that
-  totalsize = ringSize == 1 ? size : AlignUp(size, align) * ringSize;
+  totalsize = AlignUp(size, align) * RDCMAX(1U, ringSize);
   curoffset = 0;
 
   ringCount = ringSize;
@@ -208,11 +211,16 @@ void *GPUBuffer::Map(uint32_t *bindoffset, VkDeviceSize usedsize)
   VkDeviceSize offset = bindoffset ? curoffset : 0;
   VkDeviceSize size = usedsize > 0 ? usedsize : sz;
 
-  // wrap around the ring, assuming the ring is large enough
-  // that this memory is now free
+  // align the size so we always consume coherent atoms
+  size = AlignUp(size, align);
+
+  // wrap around the ring as soon as the 'sz' would overflow. This is because if we're using dynamic
+  // offsets in the descriptor the range is still set to that fixed size and the validation
+  // complains if we go off the end (even if it's unused). Rather than constantly update the
+  // descriptor, we just conservatively wrap and waste the last bit of space.
   if(offset + sz > totalsize)
     offset = 0;
-  RDCASSERT(offset + sz <= totalsize);
+  RDCASSERT(offset + size <= totalsize);
 
   // offset must be aligned
   curoffset = AlignUp(offset + size, align);
diff --git a/renderdoc/driver/vulkan/vk_memory.cpp b/renderdoc/driver/vulkan/vk_memory.cpp
index e6047b001..19892f200 100644
--- a/renderdoc/driver/vulkan/vk_memory.cpp
+++ b/renderdoc/driver/vulkan/vk_memory.cpp
@@ -178,11 +178,16 @@ void WrappedVulkan::RemapMemoryIndices(VkPhysicalDeviceMemoryProperties *memProp
 MemoryAllocation WrappedVulkan::AllocateMemoryForResource(bool buffer, VkMemoryRequirements mrq,
                                                           MemoryScope scope, MemoryType type)
 {
+  const VkDeviceSize nonCoherentAtomSize = GetDeviceProps().limits.nonCoherentAtomSize;
+
   MemoryAllocation ret;
   ret.scope = scope;
   ret.type = type;
   ret.buffer = buffer;
   ret.size = AlignUp(mrq.size, mrq.alignment);
+  // for ease, ensure all allocations are multiples of the non-coherent atom size, so we can
+  // invalidate/flush safely. This is at most 256 bytes which is likely already satisfied.
+  ret.size = AlignUp(ret.size, nonCoherentAtomSize);
 
   RDCDEBUG("Allocating 0x%llx with alignment 0x%llx in 0x%x for a %s (%s in %s)", ret.size,
            mrq.alignment, mrq.memoryTypeBits, buffer ? "buffer" : "image", ToStr(type).c_str(),
diff --git a/renderdoc/driver/vulkan/vk_outputwindow.cpp b/renderdoc/driver/vulkan/vk_outputwindow.cpp
index 86cc91a16..f7233a62e 100644
--- a/renderdoc/driver/vulkan/vk_outputwindow.cpp
+++ b/renderdoc/driver/vulkan/vk_outputwindow.cpp
@@ -721,7 +721,7 @@ void VulkanReplay::GetOutputWindowData(uint64_t id, bytebuf &retData)
   RDCASSERT(pData != NULL);
 
   VkMappedMemoryRange range = {
-      VK_STRUCTURE_TYPE_MAPPED_MEMORY_RANGE, NULL, readbackMem, 0, bufInfo.size,
+      VK_STRUCTURE_TYPE_MAPPED_MEMORY_RANGE, NULL, readbackMem, 0, VK_WHOLE_SIZE,
   };
 
   vkr = vt->InvalidateMappedMemoryRanges(Unwrap(device), 1, &range);
diff --git a/renderdoc/driver/vulkan/vk_rendertext.cpp b/renderdoc/driver/vulkan/vk_rendertext.cpp
index 3ae416f6a..a596a2605 100644
--- a/renderdoc/driver/vulkan/vk_rendertext.cpp
+++ b/renderdoc/driver/vulkan/vk_rendertext.cpp
@@ -263,7 +263,7 @@ VulkanTextRenderer::VulkanTextRenderer(WrappedVulkan *driver)
 
   // we only use a subset of the [MAX_SINGLE_LINE_LENGTH] array needed for each line, so this ring
   // can be smaller
-  m_TextStringUBO.Create(driver, dev, 4096, 10, 0);
+  m_TextStringUBO.Create(driver, dev, 4096, 20, 0);
   RDCCOMPILE_ASSERT(sizeof(StringUBOData) <= 4096, "font uniforms size");
 
   rm->SetInternalResource(GetResID(m_TextStringUBO.buf));