diff --git a/src/main/java/org/broadinstitute/hellbender/tools/sv/SVCallRecord.java b/src/main/java/org/broadinstitute/hellbender/tools/sv/SVCallRecord.java
index 8edcd595881..0f95878b389 100644
--- a/src/main/java/org/broadinstitute/hellbender/tools/sv/SVCallRecord.java
+++ b/src/main/java/org/broadinstitute/hellbender/tools/sv/SVCallRecord.java
@@ -132,8 +132,12 @@ private void validateCoordinates(final SAMSequenceDictionary dictionary) {
         Utils.nonNull(dictionary);
         validatePosition(contigA, positionA, dictionary);
         validatePosition(contigB, positionB, dictionary);
-        Utils.validateArg(IntervalUtils.compareLocatables(getPositionAInterval(), getPositionBInterval(), dictionary) <= 0,
-                "End coordinate cannot precede start");
+        // CPX types may have position B precede A, such as dispersed duplications where A is the insertion point and
+        // B references the source sequence.
+        if (type != GATKSVVCFConstants.StructuralVariantAnnotationType.CPX) {
+            Utils.validateArg(IntervalUtils.compareLocatables(getPositionAInterval(), getPositionBInterval(), dictionary) <= 0,
+                    "End coordinate cannot precede start");
+        }
     }
 
     private static void validatePosition(final String contig, final int position, final SAMSequenceDictionary dictionary) {
diff --git a/src/main/java/org/broadinstitute/hellbender/tools/sv/concordance/ClosestSVFinder.java b/src/main/java/org/broadinstitute/hellbender/tools/sv/concordance/ClosestSVFinder.java
index da4e66f3fb6..9ca5056a679 100644
--- a/src/main/java/org/broadinstitute/hellbender/tools/sv/concordance/ClosestSVFinder.java
+++ b/src/main/java/org/broadinstitute/hellbender/tools/sv/concordance/ClosestSVFinder.java
@@ -31,6 +31,7 @@
  */
 public class ClosestSVFinder {
 
+    protected final boolean sortOutput;
     protected final Map<Long, SVCallRecord> truthIdToItemMap;
     protected final Map<Long, ActiveClosestPair> idToClusterMap;
     private final SVConcordanceLinkage linkage;
@@ -49,7 +50,9 @@ public class ClosestSVFinder {
      */
     public ClosestSVFinder(final SVConcordanceLinkage linkage,
                            final Function<ClosestPair, SVCallRecord> collapser,
+                           final boolean sortOutput,
                            final SAMSequenceDictionary dictionary) {
+        this.sortOutput = sortOutput;
         this.linkage = Utils.nonNull(linkage);
         this.collapser = Utils.nonNull(collapser);
         outputBuffer = new PriorityQueue<>(SVCallRecordUtils.getCallComparator(dictionary));
@@ -60,6 +63,15 @@ public ClosestSVFinder(final SVConcordanceLinkage linkage,
         lastItemContig = null;
     }
 
+    /**
+     * Sorts output by default
+     */
+    public ClosestSVFinder(final SVConcordanceLinkage linkage,
+                           final Function<ClosestPair, SVCallRecord> collapser,
+                           final SAMSequenceDictionary dictionary) {
+        this(linkage, collapser, true, dictionary);
+    }
+
     /**
      * Should be run frequently to reduce memory usage. Forced flushes must be run when a new contig is encountered.
      * @param force flushes all variants in the output buffer regardless of position
@@ -70,8 +82,12 @@ public List<SVCallRecord> flush(final boolean force) {
                 .map(c -> new ClosestPair(c.getItem(), c.getClosest()))
                 .map(collapser)
                 .collect(Collectors.toList());
-        outputBuffer.addAll(collapsedRecords);
-        return flushBuffer(force);
+        if (sortOutput) {
+            outputBuffer.addAll(collapsedRecords);
+            return flushBuffer(force);
+        } else {
+            return collapsedRecords;
+        }
     }
 
     /**
diff --git a/src/main/java/org/broadinstitute/hellbender/tools/walkers/sv/SVConcordance.java b/src/main/java/org/broadinstitute/hellbender/tools/walkers/sv/SVConcordance.java
index f5a9d247c0a..d53c3a22b0b 100644
--- a/src/main/java/org/broadinstitute/hellbender/tools/walkers/sv/SVConcordance.java
+++ b/src/main/java/org/broadinstitute/hellbender/tools/walkers/sv/SVConcordance.java
@@ -2,6 +2,8 @@
 
 import com.google.common.collect.Sets;
 import htsjdk.samtools.SAMSequenceDictionary;
+import htsjdk.variant.variantcontext.Genotype;
+import htsjdk.variant.variantcontext.GenotypeBuilder;
 import htsjdk.variant.variantcontext.VariantContext;
 import htsjdk.variant.variantcontext.VariantContextBuilder;
 import htsjdk.variant.variantcontext.writer.VariantContextWriter;
@@ -30,8 +32,8 @@
 import org.broadinstitute.hellbender.utils.SequenceDictionaryUtils;
 import picard.vcf.GenotypeConcordance;
 
-import java.util.HashSet;
-import java.util.Set;
+import java.util.*;
+import java.util.stream.Collectors;
 
 /**
  * <p>This tool calculates SV genotype concordance between an "evaluation" VCF and a "truth" VCF. For each evaluation
@@ -50,6 +52,8 @@
  * of the specific fields. For multi-allelic CNVs, only a copy state concordance metric is
  * annotated. Allele frequencies will be recalculated automatically if unavailable in the provided VCFs.
  *
+ * For large inputs, users may enable the --do-not-sort flag to reduce memory usage.
+ *
  * <h3>Inputs</h3>
  *
  * <ul>
@@ -90,7 +94,7 @@
 @DocumentedFeature
 public final class SVConcordance extends AbstractConcordanceWalker {
 
-    public static final String USE_TRUTH_AF_LONG_NAME = "use-truth-af";
+    public static final String UNSORTED_OUTPUT_LONG_NAME = "do-not-sort";
 
     @Argument(
             doc = "Output VCF",
@@ -99,6 +103,12 @@ public final class SVConcordance extends AbstractConcordanceWalker {
     )
     private GATKPath outputFile;
 
+    @Argument(
+            doc = "Skip output sorting. This can substantially reduce memory usage.",
+            fullName = UNSORTED_OUTPUT_LONG_NAME
+    )
+    private boolean doNotSort;
+
     @ArgumentCollection
     private final SVClusterEngineArgumentsCollection clusterParameterArgs = new SVClusterEngineArgumentsCollection();
 
@@ -136,8 +146,11 @@ public void onTraversalStart() {
                 new HashSet<>(getEvalHeader().getGenotypeSamples()),
                 new HashSet<>(getTruthHeader().getGenotypeSamples()));
         final SVConcordanceAnnotator collapser = new SVConcordanceAnnotator(commonSamples);
-        engine = new ClosestSVFinder(linkage, collapser::annotate, dictionary);
+        engine = new ClosestSVFinder(linkage, collapser::annotate, !doNotSort, dictionary);
 
+        if (doNotSort) {
+            createOutputVariantIndex = false;
+        }
         writer = createVCFWriter(outputFile);
         writer.writeHeader(createHeader(getEvalHeader()));
     }
@@ -172,10 +185,32 @@ private void add(final VariantContext variant, final boolean isTruth) {
             flushClusters(true);
             currentContig = record.getContigA();
         }
+        if (isTruth) {
+            record = minimizeTruthFootprint(record);
+        }
         engine.add(record, isTruth);
         flushClusters(false);
     }
 
+    /**
+     * Strips unneeded attributes from a truth variant to save memory.
+     */
+    protected SVCallRecord minimizeTruthFootprint(final SVCallRecord item) {
+        final List<Genotype> genotypes = item.getGenotypes().stream().map(SVConcordance::stripTruthGenotype).collect(Collectors.toList());
+        return new SVCallRecord(item.getId(), item.getContigA(), item.getPositionA(),
+                item.getStrandA(), item.getContigB(), item.getPositionB(), item.getStrandB(), item.getType(),
+                item.getCpxSubtype(), item.getLength(), item.getAlgorithms(), item.getAlleles(), genotypes,
+                item.getAttributes(), item.getFilters(), item.getLog10PError(), dictionary);
+    }
+
+    private static Genotype stripTruthGenotype(final Genotype genotype) {
+        final GenotypeBuilder builder = new GenotypeBuilder(genotype.getSampleName()).alleles(genotype.getAlleles());
+        if (genotype.hasExtendedAttribute(GATKSVVCFConstants.COPY_NUMBER_FORMAT)) {
+            builder.attribute(GATKSVVCFConstants.COPY_NUMBER_FORMAT, genotype.getExtendedAttribute(GATKSVVCFConstants.COPY_NUMBER_FORMAT));
+        }
+        return builder.make();
+    }
+
     @Override
     protected boolean areVariantsAtSameLocusConcordant(final VariantContext truth, final VariantContext eval) {
         return true;
diff --git a/src/test/java/org/broadinstitute/hellbender/tools/walkers/sv/SVConcordanceIntegrationTest.java b/src/test/java/org/broadinstitute/hellbender/tools/walkers/sv/SVConcordanceIntegrationTest.java
index 7f846624de4..6f4157724d4 100644
--- a/src/test/java/org/broadinstitute/hellbender/tools/walkers/sv/SVConcordanceIntegrationTest.java
+++ b/src/test/java/org/broadinstitute/hellbender/tools/walkers/sv/SVConcordanceIntegrationTest.java
@@ -38,7 +38,7 @@ public class SVConcordanceIntegrationTest extends CommandLineProgramTest {
 
     @Test
     public void testRefPanel() {
-        final File output = createTempFile("concord", ".vcf");
+        final File output = createTempFile("concord", ".vcf.gz");
         final String evalVcfPath = getToolTestDataDir() + "ref_panel_1kg.cleaned.gatk.chr22_chrY.vcf.gz";
         /**
          * Test file produced from raw standardized VCFs from manta, melt, wham, and cnv callers with SVCluster parameters:
@@ -171,7 +171,7 @@ public void testSelf() {
 
         // Run a vcf against itself and check that every variant matched itself
 
-        final File output = createTempFile("concord", ".vcf");
+        final File output = createTempFile("concord", ".vcf.gz");
         final String vcfPath = getToolTestDataDir() + "ref_panel_1kg.cleaned.gatk.chr22_chrY.vcf.gz";
 
         final ArgumentsBuilder args = new ArgumentsBuilder()
@@ -260,7 +260,7 @@ public void testSelfEvalSubset() {
 
         // Run a vcf against itself but with extra samples and variants
 
-        final File output = createTempFile("concord", ".vcf");
+        final File output = createTempFile("concord", ".vcf.gz");
         final String evalVcfPath = getToolTestDataDir() + "ref_panel_1kg.cleaned.gatk.chr22_chrY.sample_subset.vcf.gz";
         final String truthVcfPath = getToolTestDataDir() + "ref_panel_1kg.cleaned.gatk.chr22_chrY.vcf.gz";
 
@@ -322,7 +322,7 @@ private void assertPerfectConcordance(final File output, final String evalVcfPat
 
     @Test
     public void testSitesOnly() {
-        final File output = createTempFile("concord_sites_only", ".vcf");
+        final File output = createTempFile("concord_sites_only", ".vcf.gz");
         final String evalVcfPath = getToolTestDataDir() + "ref_panel_1kg.cleaned.gatk.chr22_chrY.sites_only.vcf.gz";
         final String truthVcfPath = getToolTestDataDir() + "ref_panel_1kg.raw_calls.chr22_chrY.sites_only.vcf.gz";
 
@@ -358,7 +358,7 @@ public void testSitesOnly() {
 
     @Test(expectedExceptions = UserException.IncompatibleSequenceDictionaries.class)
     public void testHeaderContigsOutOfOrder() {
-        final File output = createTempFile("concord_sites_only", ".vcf");
+        final File output = createTempFile("concord_sites_only", ".vcf.gz");
         final String evalVcfPath = getToolTestDataDir() + "ref_panel_1kg.cleaned.gatk.chr22_chrY.vcf.gz";
         final String truthVcfPath = getToolTestDataDir() + "ref_panel_1kg.cleaned.gatk.chr22_chrY.contigs_out_of_order.vcf.gz";
 
@@ -370,4 +370,24 @@ public void testHeaderContigsOutOfOrder() {
 
         runCommandLine(args, SVConcordance.class.getSimpleName());
     }
+
+    @Test
+    public void testSelfUnsorted() {
+
+        // Run a vcf against itself but don't sort the output
+
+        final File output = createTempFile("concord", ".vcf");
+        final String evalVcfPath = getToolTestDataDir() + "ref_panel_1kg.cleaned.gatk.chr22_chrY.vcf.gz";
+        final String truthVcfPath = getToolTestDataDir() + "ref_panel_1kg.cleaned.gatk.chr22_chrY.vcf.gz";
+
+        final ArgumentsBuilder args = new ArgumentsBuilder()
+                .addOutput(output)
+                .add(StandardArgumentDefinitions.SEQUENCE_DICTIONARY_NAME, GATKBaseTest.FULL_HG38_DICT)
+                .add(AbstractConcordanceWalker.EVAL_VARIANTS_LONG_NAME, evalVcfPath)
+                .add(AbstractConcordanceWalker.TRUTH_VARIANTS_LONG_NAME, truthVcfPath)
+                .add(SVConcordance.UNSORTED_OUTPUT_LONG_NAME, true);
+
+        runCommandLine(args, SVConcordance.class.getSimpleName());
+        assertPerfectConcordance(output, evalVcfPath);
+    }
 }